| TERM |
DEFINITION |
| Abrasion |
These are little nicks along facet junctions which produce white fuzzy lines rather than sharp crisp facet edges. |
| Bezel |
Located above the girdle, this is a facet on the crown or upper part of the diamond.
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| Blemish |
Used to describe a clarity characteristic, a blemish occurs on the surface of a diamond. It is an imperfection external to the diamond. |
| Brilliance |
This is the diamond's light-reflection power. It is the white light that reflects up through the top of a diamond. Cutting a diamond to the correct proportions increases the reflection of light from the facets and amplifies the brilliance.
It is this effect that makes diamonds unique among all other gemstones. Although other gemstones also display brilliance, no other gem has the power to equal the extent of diamond's light-reflecting power.
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| Brilliant Cut |
This cut is a 57-facet round diamond. The shape and faceting arrangement are designed for the greatest brilliance, fiery sparkle and beauty.
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| Carat |
A carat is the unit of weight for a diamond and is equivalent to 200 milligrams, or one-fifth of a gram. It is believed that the word carat word comes from ancient India where the carob bean was used for measuring the weight of gems. This bean has the rare property that every seed weighs the same - 200 milligrams.
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| Cavity |
An inclusion consisting of a large or deep hallow area in the diamond.
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| Chip |
A small broken off piece caused by normal wear and tear or by cutting.
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| Clarity |
Clearness of the diamond. This is a grade given to a diamond to describe the level of impurities or inclusions.
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| Cloud |
A cluster or group of tiny inclusions inside a diamond that produces a milky or cloudy effect. Although tiny clouds will not interfere with the flow of light, large or numerous clouds can affect brilliance.
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| Color |
A grade given to a diamond to describe the delicate shades of hue or color. D being perfectly colorless and also the most rare and expensive color. Moving through the scale from D to Z indicates increasing levels of gray, brown and yellow tones. Normally only a trained eye using special lighting can distinguish between neighboring color grades (such as E to F), but most people, with a little practice, can tell the difference the difference between colors that are several grades apart. Rare and fancy colors such as pink, red, blue and green are very rare and extremely expensive. These fancy colors do not follow the normal color pricing scales and are classified differently.
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| Culet |
The point on the very bottom of a diamond which is actually a facet. It is best to have a small or medium point or culet, but it shouldn't be too large or flat. If it is large, it will look like there is a hole in the bottom of the stone due to escape of light. Lack of a culet will make the point of the diamond more easily damaged or chipped.
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| Cut |
The term “cut” does not signify a diamond's “shape”. It is rather the attempt of the artisan to make the best use of light. The cut unlocks the diamond's hidden beauty and is the result of a skillful and talented diamond cutter.
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| Depth % |
The height of a diamond measured from the culet [bottom] to the table [top] divided by the width of the diamond. The depth % is crucial to generating the brilliance and fire in a diamond. If the depth % that is too low or too high, it will cause light to seek out of the stone, causing the diamond to lose its sparkle.
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| Dispersion |
Dispersion is the reflected white light and colored flashes or fire of a diamond.
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| Excellent Cut |
A GIA and HRD-CGL diamond cutting grade for excellent cut and polish of brilliants.
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| Eye-Clean |
A diamond that has no inclusions when viewed with the naked eye. As a general rule, this is true of all diamonds with a clarity grade of about SI-1 or higher.
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| Facet |
The plain polished flat surfaces on a diamond. For example, a round brilliant diamond has 58 facets when counting the culet.
Extra Facet - A facet placed without regard for symmetry and which is in excess of those typically used to complete the faceting pattern for the given cutting style.
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| Fair Cut |
Diamonds cut to less perfect proportions and as a result are less expensive. They have been cut to maximize the weight of the stone, and sacrifice fire and sparkle.
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| Feather |
A separation or break due to either cleavage or fracture, often white and when viewing at an angle, this gives the appearance of a feather. |
| Finish |
The word finish is used to describe the exterior of the diamond. The finish is also referred to as the “polish”. |
| Fire |
The brilliance, or flashes of colored light reflected from within a diamond. White light entering a stone is separated into the color spectrums like a rainbow or prism. High-quality fire can only be achieved with very good to excellent proportions.
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| Fluorescence |
A glow or shine, typically of a bluish color, which radiates from certain diamonds when exposed to high ultraviolet light. Most buyers prefer faint blue fluorescence because it allows a less expensive yellowish color appear more while or colorless. In daylight a strong blue fluorescence can appear to be oily.
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| Flaw |
An imperfection in a diamond.
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| Fracture |
A crack on the diamond's surface. |
| Girdle |
The outer edge or narrow band around the outer perimeter of a diamond. The jewelry mounting usually holds the diamond around the girdle. Girdles can be rough (looks like it was sand papered) or faceted (polished). Either method works well since it makes no difference to the overall beauty of the diamond.
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| Good Cut |
A diamonds cut that is acceptable, but does not have perfect proportions. As a rule, they have very good brilliance and fire and make excellent jewelry.
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| Hue |
The term used for the pure, spectral (prismatic) color. The more pure a gemstone's hue, the more valuable it is. Diamonds typically give off one primary color and one or more underlying colors including gradations and mixtures of red, orange, yellow, green, blue, violet and violet.
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| Ideal Cut |
The Ideal Cut represents what some professionals consider a perfectly proportioned diamond, meaning it has the depth percentages and table percentages that produce a "perfect" balance of fire and brilliance. This cut almost always has the highest grades on polish and symmetry as well, indicating the great craftsmanship of the overall design of the stone. Ideal Cut diamonds are usually more expensive than all other cut grades.
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| Inclusion |
An imperfection is internal to the diamond which interrupts the flow of light, such as a spot or irregularity within the structure of the stone. These impurities can be a cloud, a fracture, another diamond inside a bigger diamond, liquid, etc. Inclusions can either be visible with the naked eye (usually SI-3 clarity and below) or the can be visible only under magnification. Fewer inclusions means a finer clarity grade, increased rarity, and, of course, increased value.
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| Make |
The quality of a completed diamond's finish and its proportions. A good make will have proportions that capitalize on its brilliance and fire. A poor make will reduce sparkle and fire due to less light being able to travel through the stone.
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| MOH Scale |
The 10-point scale of mineral hardness. Diamond scores 10 on Mohs Scale as they are the hardest of all known natural substances. |
| Pavilion |
The pavilion is the bottom half of a diamond, from the lower girdle to the culet at the bottom tip. When a pavilion is too deep or shallow, the light will escape and the diamond will lose fire and brilliance.
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| Point |
A point is a measurement of diamond weight. One point is equal to 1/100th of a carat. A diamond that weighs 0.50 carat is said to weigh 50 points, and one that is 2.00 carats is 200 points. This does not refer to the number of facets in the diamond.
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| Polish |
A grade given to the external finish (smoothness) of a diamond. Grades range from poor to excellent. Good polish is critical to the utmost brilliance of a diamond. However, it does take a trained eye to differentiate between the different polish grades.
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| Poor Cut |
This cut refers to diamonds with proportions and finish that make them look relatively unexciting to the eye. A poorly cut diamond can be either cut too deep or too shallow. A diamond that is cut too deep or shallow will lose or leak light through the side or bottom resulting in less brilliance and a lower value.
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| Scintillation |
An older term that simply means the sparkle of a diamond. Scintillation may also be explained as the flashes of brilliance and dispersion that are seen in a diamond when either the observer or the diamond is moving. Hence scintillation is witnessed when the observer moves his or her head while looking at the diamond or when it is seen from across the room as a person walks by.
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| Sparkle |
The mixture of fire and brilliance in a diamond or the amount of light that reflects out of a diamond as it moves. This is sometimes called "scintillation" by older dealers.
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| Symmetry |
A diamond cutter creates symmetry by the arrangement of the facets and finished angles. Most labs grade symmetry as Excellent, Very Good, Good, Fair or Poor. Poor symmetry will hurt a diamond's sparkle and fire, due to loss of light as it flows through the stone and out to your eye.
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| Table % |
The width of the table divided by the total diameter of the diamond. The table % is most significant to creating sparkle and fire in a diamond.
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| Table |
The largest flat facet on the top a diamond. This is where most of the light enters and exits a diamond. However, if the table facet is too large or too small, it often points to poor proportions overall. Poor proportions will hurt a diamond's fire and brilliance.
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