| Baguette | A rectangular style of step cut commonly used as an accent stone in a setting. |
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| Blemish | An imperfection on the surface of a gemstone. |
| Brilliance | The total amount of white light reflected from the stone. Cut, number of inclusions, color and polish can all affect a diamond?s brilliance. |
| Brilliant Cut | The most common style of diamond cutting. Brilliant cut is also referred to as round cut. It is number one in brilliance and the most sparkling of all cuts with the exception of Princess Plus. |
| Carat | Unit of measurement used to weigh diamonds and other gemstones. One carat equals .2 grams. Abbreviated ct. |
| Certificate Number | Each gemstone is given a unique certificate number. US means the gem was certified in the United States, CA means it was certified in Canada. If you would like to verify your certificate, visit www.eglusa.com. |
| Clarity Grade | Refers to the number of blemishes and inclusions in and on a diamond. Grades range from flawless (no inclusions) to included (visible inclusions). One of the 4C's. |
| Color Grade | Ungraded diamonds are carefully compared to a master set of diamonds with known color grades. EGL standards require two color graders plus a final grader to agree upon the color of the diamond before a color grade is assigned. |
| Comfort Fit | A style of men’s wedding rings where the inside of the band is rounded. This raises the ring just enough so it is not flush with the finger. The extra space creates a cushion so that the finger never feels pinched or squeezed by the ring. |
| Crown | Crown Percentage is the comparison of the height of the crown to the depth of the diamond. |
| Culet | The culet is the facet located on the pointed tip of the diamond. Culets range in size from very small to very large. If a diamond does not have a faceted tip, the word NONE will appear on the certificate. |
| Depth | Depth Percentage is a comparison of the depth of a diamond to the width of a diamond. |
| Diamond | A mineral composed of carbon with a hardness of 10. |
| Durability | Describes a gemstone?s ability to resist wear. |
| Emerald Cut | A style of cutting a diamond or gemstone where the outline is a rectangle with cut corners and the facets are rectangular as well. |
| Facet | The many small cuts on a gemstone that are polished to increase sparkle, shine and brilliancy. |
| Fire | Flashes of spectral colors given off by a gemstone. Fire is also referred to as scintillation. |
| Fluorescence | EGL rates fluorescence on a scale from NONE to VERY STRONG. Fluorescence refers to the visible light a diamond emits while under an ultraviolet light. Most often, the light emitted is blue, but other hues are possible. If fluorescence is rated higher than FAINT and the color is one other than blue, it will be noted on the certificate. |
| Four C's | An industry standard by which all diamonds are judged. Includes cut, color, clarity and carat weight. |
| Girdle | Girdle refers to the narrow band circling the widest part of the diamond. Girdles range from extremely thin to extremely thick and are either faceted, polished or unpolished. |
| Hardness | A gem's ability to resist scratching. |
| Inclusion | Internal flaws present in diamonds and other gemstones. A "carbon spot" is a black spot caused by carbon within the stone. A "feather" is a white line caused by air trapped within the stone. |
| Marquise | A cutting style for diamonds and other gemstones where the outline is an elliptical shape with pointed ends. |
| Measurements | Stated in millimeters. The three numbers listed are Maximum x Minimum x Depth for a round cut diamond and Length x Width x Depth for a fancy shaped diamond. |
| Metal | Yellow gold, white gold and platinum are the precious metals commonly used to craft fine jewelry. |
| Mounting | The part of the jewelry that actually holds the gem. |
| Oval Cut | A gemstone cutting style where the girdle outline forms an elliptical or oval shape. |
| Pavé | A jewelry setting style where the small stones are placed as close together as is possible. Usually in rows of two or more. |
| Pavilion | Pavilion Percentage is the comparison of the height of the pavilion to the total depth of the diamond. |
| Pear-Shaped Cut | A gem cutting style where the girdle outline forms the shape of a teardrop or pear. |
| Plotting Diagram | A schematic diagram included on the EGL USA Diamond Certificate where the facets are printed in black and the approximate location and type of internal and external characteristics are printed in red (man-made) and green (naturally occurring). |
| Points | Diamonds are usually discussed in points. Example: 1 point = .01 ct.; 50 points = .50 ct.; 100 points = 1.00 ct. |
| Polish | Polish refers to the quality of the surface of the facets. Polish grades include: Poor, Fair, Good, Very Good and Excellent. |
| Polished Girdle | A polished girdle is smooth and highly reflective. |
| Proportions | The characteristics that comprise cut. Cut influences the sparkle of a diamond. |
| Rhodium | A metal alloy known for strength. Commonly applied as a coating to white gold to strengthen the metal and make it appear whiter. |
| Shape and Cut | Shape refers to the literal shape of the diamond itself. Common shapes include: Round, Emerald, Heart, Marquise, Oval, Pear, Princess and Radiant. Cut refers to the way the facets are cut. Brilliant cut diamonds have triangular facets. Step cut diamonds have rectangular facets. |
| Single Cut | A diamond that is smaller than .01 carat and has 16 or 17 facets. It is commonly used in pave jewelry and other jewelry with closely set stones. |
| Solitaire | A ring or other piece of jewelry containing one single diamond or gem. |
| Star Facets | triangular facets that surround the table facet of a brilliant-cut diamond. |
| Symmetry | Symmetry refers to the overall symmetrical shape of the diamond. Symmetry ratings include: Poor, Fair, Good, Very Good and Excellent. |
| Table | The flat top surface of a gemstone. |
| Tone | The color attribute that determines the lightness or darkness of shading. |
| Toughness | The ability of a stone to resist breaking or fracturing. |
| Weight | Weight is measured in carats. This is the international standard. One carat weighs .20 gram. |
| White Gold | Gold alloyed with silver, zinc or platinum. The alloys act as whitening agents. |
| Yellow Gold | The natural color of pure gold. When alloyed for karat gold, certain metals are used to maintain the golden color. |
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