Glossary
Terms in glossary: 11.
Brilliance
Relating to, or being a hue taht has a strong combination of lightness and strong saturation
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Carat
Carat, abbreviated "ct." is a measure of weight used for diamonds. One carat is equal to 1/5 of a gram (200 milligrams). Stones are measured to the nearest hundredth of a carat. A hundredth of a carat is also called a point. Thus a .10 carat stone can be called either 10 points, or 1/10 of a carat. Small stones like .05, and .10ct are most often referred to by point designations.
The carat, as a unit of weight, is derived from the carob seed which was used by early gem traders to weigh diamonds. Since a carat is a unit of measure and not size, two diamonds of the same carat weight may appear to be different sizes depending on how the diamond is cut.
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Clarity
Clarity is an indication of a diamond's purity and is evaluated by viewing the stone under 10x magnification. See below the differences between what you see with the naked eye compared with what you can see with a 10x magnifying loupe. A diamond that is virtually free of interior or exterior inclusions is of the highest quality for nothing interferes with the passage of light through the diamond.
Every diamond is unique and possesses its own individual natural characteristics referred to as inclusions and described as "nature's fingerprints". These inclusions, such as minerals or fractures, appear while diamonds are formed in the earth. They may look like tiny crystals, clouds or feathers. The number, size, color, nature and position of the inclusions determine the clarity of the diamond.
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Color
Color refers to the presence or absence of color in white diamonds.
Color differences are very subtle and it is very difficult to see the difference between say, an E and an F. Therefore, colors are graded under controlled lighting conditions and are compared to a master set for accuracy. When determining the color of a diamond, it is crucial to see the diamond unmounted.
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Crown
The top part of a cut stone, above the girdle
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Cut
Diamonds can have cut grades of Ideal, Very Good, Good, Fair, and Poor. The cut, or proportions and angles of a diamond determine how it reflects light. A diamond's reflective properties are referred to as "fire" or "brilliance." Too shallow a cut will let light escape through the sides of the diamond before it has a chance to reflect, making it appear watery or dull, while too deep a cut will allow light to be lost through the bottom of the diamond, making it appear dark, especially in the center.
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E. G. L.
European Gemological Labratory: EGL is one of the world's premier independent gemological laboratories. For over 25 years it has offered the fine jewelry trade and consumers accurate, reliable gemstone identification and professional certification to validate their gemstone purchases.
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Fluorescence
Normally invisible wavelengths of light that become "visible" when exposed to ultraviolet radiation. Gems or pearls that exhibit colour under ultraviolet light, colour not normally seen in normal light, are exhibiting "fluorescence".
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G. I. A.
Gemological Institute of America: Established in 1931, GIA is the world’s largest and most respected nonprofit institute of gemological research and learning. Conceived 75 years ago in the august tradition of Europe’s most venerated institutes, GIA discovers (through GIA Research), imparts (through GIA Education), and applies (through the GIA Gem Laboratory and GIA Gem Instruments) gemological knowledge to ensure the public trust in gems and jewelry.
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Girdle
Girdle
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I. G. I.
International Gemological Institute: The International Gemological Institute (IGI) is the largest independent gem grading and appraisal institute in the world, renowned for their expertise and extensive experience in serving the diamond and jewelry industry for over 25 years.
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Glossary