4C'S LEARNING CENTER
Be confident you're getting the best diamond for your money. Here you'll find unbiased information to help take the anxiety
out of this exciting time. We don't buy or sell diamonds and we don't get commissions for recommending certain retailers.
Be confident you're getting the best diamond for your money. Here you'll find unbiased information to help take the anxiety out of this exciting time. We don't buy or sell diamonds and we don't get commissions for recommending certain retailers.
DIAMOND CUT
4C's - Shape & Cut
Don't confuse Shape & Cut - they are not the same thing. Shape refers to the outline or silhouette of a diamond, such as Round, Heart, or Square (aka Princess) and Cut refers to the quality of faceting and the diamond's light handling ability.
What are the most popular Diamond Shapes?
The Round Brilliant Cut is the most popular, but there are several other popular diamond shapes and hundreds of variations on these shapes. Known as 'Fancy Shapes' these include: Oval, Cushion, Princess, Radiant, Emerald, Asscher, Marquise, Pear, and Heart.
Which diamond shape looks the biggest?
Elongated shapes, such as Ovals, Marquise and Emeralds can look bigger for their carat weight compared to other shapes of the same weight. Diamonds with shallower depths look larger face up, but be careful not to sacrifice too much brilliance.
What is the best shape of diamond?
Choosing the shape that's right for you is all about personal preference, which one do you like the most? Round Brilliants are considered to be the most mathematically Ideal shape for diamonds and have the most sparkle, but choosing a Fancy Shape instead can save you money
Which diamond shape is the most expensive?
Generally speaking, when comparing diamonds of equal size and quality, Rounds are the most expensive shape followed by Heart, Oval, Asscher, Pear & Marquise and then Emerald, Radiant, Cushion & Princess. The price difference between rounds and princesses can be as little as 0-20% in lower colors and clarities, and as great as 100% in larger sizes and higher colors and clarities. Read more about How Shape Affects Price
What is Cut?
Cut is a word with several meanings. The first meaning of Cut refers to the Shape of a stone - round, oval, rectangular, marquise, pear, or heart. Another meaning refers to the shape of individual facets - Brilliant cuts have triangular and kite shaped facets, whereas Step cuts have rectangular and trapezoid shaped facets.
The most important meaning of Diamond Cut refers to a diamond's light handling ability and involves aspects of craftsmanship, including dimensions, angles, symmetry, faceting and polish.
Which of the 4C's is most important?
In our opinion, Cut. A well Cut diamond is beautiful regardless of its carat weight, color or clarity.
A diamond is the ultimate light-handling machine. A well Cut diamond is a masterpiece of optics designed to return light to its owner's- or admirer's eye. To unleash maximum brilliance, fire and sparkle, a diamond must be manufactured with the same expert skill and precision as a fine automobile. This means Cutting is as much the key to diamond performance as engineering is the key to car performance.
Think of diamond buying as, in part, like taking a gem for a test-drive. Just as you base a car purchase on a vehicle's physical performance, you base your diamond purchase on its visual performance.
Is there a standard diamond Cut?
The most popular and 'standard' diamond shape is the round brilliant. The round brilliant is designed to maximize the light performance of a diamond. After years of extensive study, the modern round brilliant has evolved to have a narrow range of acceptable proportions that maximize the optical potential of a diamond and produce the best combination of brilliance, fire and sparkle.
An 'Ideal Cut' is the highest standard. A diamond that achieves Excellent ratings in the categories of Light Performance (optical brilliance and optical symmetry), Finish (polish and external symmetry) and Proportions (table size, depth %, crown angle, pavilion angle and girdle thickness) is considered an 'Ideal Cut'.
How many facets does a diamond have?
It depends on the shape and cutting style. A standard round brilliant has 57 or 58 facets, an emerald step has 49 or 50 facets, a princess has 53 facets, etc.
Some shapes have over 100 facets, but more facets do not necessarily equal more brilliance, it just means that the light is broken up into more rays and reflected in more directions.
Even tiny diamonds, as small as 1-point (0.01ct), are commonly faceted as round brilliants with 57 facets.
What are the different parts of the diamond?
The main parts of a diamond are:
Table
Crown
Girdle
Pavilion
Culet
How do I know if a diamond is a good Cut?
The abridged answers...
Look and see for yourself.
Buy a diamond that you think is beautiful.
Buy a diamond that you fall in love with.
Ask for a diamond with a GCAL 'Ideal Cut' or GCAL '8x' certificate.
The unabridged answer...
Grading every aspect of Cut quality falls into two categories - proportions and craftsmanship.
Proportions = Light Return
Diamonds are cut to exact proportions that have evolved over the last hundred years of study. The interrelationship between these proportions- table size, crown angle, pavilion angle, girdle thickness, and culet size- determine how much light that enters the diamond is returned to the observer's eye in sufficient strength to give the stone full beauty and vitality. This is called light return.
Light return, which is determined by proportions, is described as:
- Brilliance (the overall brightness and light returned to a viewer's eye)
- Fire (dispersive colored light like rainbows from a prism)
- Scintillation (the sparkle you see when a diamond moves)
Because proportions directly influence light return, some people assess cut quality based on proportions alone. They measure parts of the diamond and then either: (1.) determine which grade range the proportions fall within on standard measurement grading charts, or (2.) rely on software to make a digital model of the diamond that tries to predict what the diamond looks like.
Judging cut based on two-dimensional mathematics or theoretical modeling is not the best way to evaluate light performance because it doesn't take into account slight nuances of faceting, shape, and clarity features.
The best way to judge cut quality is to analyze the actual light return coming from the real diamond. This is how GCAL's proprietary direct assessment light performance technology works. We photograph the diamond in an environment that clearly distinguishes where light 'leaks' out the bottom of the diamond. Then we scientifically calculate the percentage of light leakage versus light return.
On every GCAL certificate, the Optical Brilliance image allows you to see for yourself exactly how much light is coming from the diamond. The dark blue areas are the light leakage and the white areas are the light return. This is the simplest way to know that your diamond is well cut and has good proportions - no need to worry about numbers, angles and percentages.
Craftsmanship = Symmetry
Craftsmanship is a judgment of the diamond cutter's workmanship. When a diamond cutter transforms a diamond-in-the-rough into a beautiful gemstone, they first must properly proportion all the angles, and then they must finish each facet with skill, patience and artistry. This is graded as polish and symmetry.
Polish refers to the final finish of each facet. If the diamond's surface is microscopically smooth and free of scratches then it gets an excellent rating. The more scuffs, the less the rating.
Symmetry is an assessment of each facet's precise shape, placement, and alignment. Symmetry is graded in two ways:
- External Symmetry assesses the physical symmetry of each facet and is graded by examining the diamond under 10x magnification.
- Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return. This is graded by placing the diamond in an optical symmetry reader that reveals the patterns of light return. The Optical Symmetry image on every GCAL certificate is a photograph of the diamond captured while in the optical symmetry reader.
You can see the quality of the cut by looking at the Optical Symmetry image on your GCAL certificate - the more even the pattern, the better the symmetry. All light returned at the same angles is represented by the same color. For example, red areas represent light being returned within a consistent angle range, green areas represent a different angle range, etc.
Each panel of a GCAL Certificate tells a story to the customer.
- Panel 1
Verifies the identification process
- Panel 2
Verifies the 4C's quality grading
- Panel 3
Illustrates the quality of cutting and proportions revealing the skill of the diamond cutter
- 1Gemprint
GEMPRINT
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 2Laser Inscription
Laser Inscription
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 34C's Grading
4C's Grading
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 4Photomicrograph
Photomicrograph
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 5Hearts & Arrow
Hearts & Arrow
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 6Optical Brilliance
Optical Brilliance
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 7Optical Symmetry
Optical Symmetry
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
- 8Proportion Diagram
Proportion Diagram
Gemprint
Gemprint® is a non-invasive, positive identification technology that records the unique optical 'fingerprint' of each diamond. Just like a human fingerprint, every diamond has a unique Gemprint. Capturing the unique Gemprint of your diamond in the initial processing stage, allows us to positively identify and track the diamond through our process. This optical fingerprint is captured and stored in GCAL's database for future verification and identification, and a digital image is printed on every GCAL Certificate.
How it works:
Gemprint uses a sophisticated system comprising laser technology, high resolution imaging, and automated positioning to direct a focused laser beam at the center of the diamond. The light enters the diamond and is broken into many rays as it reflects and refracts off the pavilion and crown facets. As the light reflects back out of the diamond, it creates a distinct Gemprint.
Laser Inscription
Laser Inscription quickly identifies a diamond and is included with this GCAL Guaranteed Diamond Grading Certificate. GCAL certified diamonds are laser inscribed with the unique certificate number assigned to the diamond. Photomicrographs, captured at more than 50x magnification, are taken to easily communicate what is inscribed on your diamond, and can be used as an additional piece of forensic identification of your diamond.
How it works:
GCAL uses a sophisticated IR laser technology specially designed for inscribing gemstones. When this laser is focused on a diamond's surface, it graphitizes a microscopic mark. A continuous series of these marks produces the numbers and letters you see on the girdle. The laser inscription mark is extremely shallow, only about 2-5 microns deep, less than one-tenth the width of the average human hair.
4Cs GRADING
WEIGHTS & MEASUREMENTS
Precise measurement of carat weight is important - slight differences can have a large impact on the value of a diamond. GCAL weighs diamonds on precise electronic balances according to international standards. This means that the weight is measured to the thousandth of a carat, and then is rounded to the hundredth of a carat. The electronic balances at GCAL are verified daily to ensure consistent and accurate results. The diamond is then measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
COLOR
Diamonds are color graded on a scale from D to Z. Each letter represents a slightly more saturated color. Your diamond is examined in a standard lighting environment and is compared to a set of Precision Master Color diamonds, which each have a precise color grade. Comparison of your diamond to the Precision Master diamonds continues until the color grade is determined. The difference between each color grade is very slight, but with experience, expert graders are able to consistently determine the accurate color grade of each diamond. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond. (After color grading, your diamond is checked for fluorescence, its reaction to ultraviolet light. A set of Master fluorescent diamonds is used to compare the strength of fluorescence. This intrinsic property is a permanent identifying characteristic of your diamond.)
CLARITY
Clarity is graded by examining your diamond under a microscope to assess internal and external characteristics such as crystals and feathers. A gemologist first inspects the diamond in the face-up position to find obvious inclusions. To find minute inclusions, the diamond has to be viewed through the pavilion as it is slowly rotated at least 3 full times, changing the viewing angle each time. The gemologist must assess the number, size, type, position and relief of each inclusion. After thorough inspection under the microscope, a 10x loupe is used to view the diamond in 4 different positions to determine the final clarity grade. GCAL utilizes a unique quality control procedure for grading the color and clarity of diamonds that assures the most accurate and consistent grading possible. At least three experienced gemologists examine and grade both the color and the clarity of every diamond.
RESEARCH
Before grading, every diamond is tested to confirm its origin - either natural earth mined or lab grown. If a diamond's origin cannot be verified by the initial spectroscopic analysis, then it is sent to the research department where additional more advanced tests are used to determine its authenticity. Considerable investment in state-of-the-art technologies has made GCAL one of the most well-equipped gem labs in the world. Once your diamond's origin is determined, it is ready for grading.
Photomicrograph
Photomicrographs are taken of the crown and pavilion of your diamond. These photos provide a forensic record of the exact appearance and condition of your diamond, and show internal and external characteristics visible at 10x magnification. Photographs are the most accurate way to illustrate the exact appearance and location of inclusions.
HEARTS & ARROWS
Hearts & Arrows is a term used to describe the patterns visible in perfectly faceted round brilliant cut diamonds when they are examined in specialized viewers. Through these viewers, it is possible to assess the alignment and consistency of every facet by looking at the equality of light return, or the hearts and arrows patterns.
A precisely faceted round brilliant diamond exhibits a pattern of eight arrows through the crown (top) side, and a pattern of eight hearts through the pavilion (bottom) side.
GCAL is the only laboratory that takes a real photograph of each diamond in the specialized viewer. This means that the images on your GCAL Certificate are actually of your diamond. Unlike the majority of the Hearts & Arrows photos printed on other lab reports or seen online, which are either generic sample images applied to every diamond or are computer generated - neither of which guarantees that the diamond you're paying a premium for is actually deserving of the term Hearts & Arrow.
OPTICAL BRILLIANCE
GCAL directly assesses the overall return of light to the viewer, called 'brilliance'.
The Optical Brilliance image is actually a digital photograph of the diamond taken in a special lighting environment that creates a strong contrast between the bright and dark areas. The image is then processed in a proprietary computer program that calculates the percentage of brilliance and the amount of light loss. This is a scientifically accurate and repeatable way to measure brilliance. The light gray areas of the image are facet outlines resulting from image processing to provide a realistic representation of the diamond's unique faceting.
In the Optical Brilliance Analysis image on the certificate, the white represents the light return and the blue represents areas of light loss. The light return is quantified based on measurable light return (aka - performance) and then graded as: Excellent, Very Good, Good, Fair or Poor.
Since the Optical Brilliance is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the brilliance image of each individual diamond will always look slightly different.
Brilliance is what gives a diamond its life, and what makes a diamond shine from across a room. Diamonds with a low percentage of brilliance look dull and dark.
OPTICAL SYMMETRY
The Optical Symmetry Analysis image is a digital photograph taken of each diamond in a special lighting environment that reveals the patterns of light return. All light returned at the same angles is represented by the same color. For example, all red areas represent light being returned within a consistent angle range. Therefore, the Optical Symmetry assesses the consistency of angles and alignment of facets by looking at the equality of light return.
Since the Optical Symmetry is measured by direct assessment, meaning that it is judged based on the way each diamond actually performs rather than a theoretical model, the symmetry images of each individual diamond will always look slightly different. Like the beauty and ever changing color patterns in a kaleidoscope, each diamond reveals its unique reflective pattern of symmetry. You can judge the cut of a diamond yourself simply by examining the symmetry image-the more even the pattern, the better the symmetry
PROPORTION DIAGRAM
Each diamond is measured by an optical scanning device that captures a series of high resolution images and creates an exact 3D model of every facet and angle, providing accurate geometrical measurements of the diamond. This proportion diagram appears on your GCAL certificate.
