Baguette A step-cut style of cut developed in the early 20th century. Derived from the French word for "rod", this rectangular cut normally has 14 facets and is used for side stones.
Bezel Refers to 8 kite-like facets located on a diamond's crown, sloping just above the girdle and below the table. A bezel setting wraps entirely around the diamond at the girdle.
Blemish Any mark, scratch, nick, abrasion, knot or other flaw on the surface of a diamond. This can affect clarity.A blemish can occur naturally or be the result of polishing.
Brilliance Brilliance is the measure of white light that has entered and is then reflected back to the human eye when a diamond is viewed table up. This is a direct result of the diamond's cut.
Brilliant Cut The brilliant cut is the most popular diamond cut style and was developed to maximize a diamond's brilliance. The most common brilliant cut is the round brilliant, consisting of 58 facets (including the culet), but there are also modified brilliant cuts resulting in different shapes.
Carat Weight Carat weight is the measurement used for the weighing of a diamond. A single carat is equal to 200 milligrams, or 1/5th of a gram (1/142nd of an ounce). The carat can be divided into 100 points, with 100 points equaling one carat.
Carbon Spots These are small, dark-appearing diamond inclusions that, upon close inspection, are usually seen to be clear diamond crystals, clear mineral crystals or cleavages. Rarely actually carbon, the apparent darkness of these "spots" is normally the result of light reflection.
Cavity Cavities are holes within the diamond's surface.They are normally the result of polishing (in which a knot or feather is polished out, leaving a hole), cleavage or a blow to the surface.
Chip A small curved, cleavage inclusion, normally emanating from the diamond's surface.
Clarity Clarity is one of the 4Cs and is the measure of a diamond's light properties.It is graded on a scale of "FL" (Flawless) to "I" (Imperfect). Clarity grade is determined by the level of inclusions and blemishes seen in and on the diamond with a 10X loupe.
Colour One of the 4Cs and a measure of the level of color seen within the diamond. The GIA color grading system of "D" (or colorless) to "Z" grades color according to a diamond's light absorption and the amount of trace elements present within a given diamond.
Crown The crown is the top portion of the diamond. The crown begins above the girdle, or widest portion of the diamond, and consists of the table, or top, and a varying number of facets.
Crown Angle The crown angle is the degree of the angle formed between the table and the girdle. This angle determines the bezel facet positions and, subsequently, the amount of fire or dispersion seen in the diamond.
Culet This is the point at the bottom of the diamond.It can be polished into a facet parallel to the girdle (the smallest facet on a diamond) or made into a point.
Cut Considered by many to be the most important of the 4Cs, CUT is the greatest determinant in a diamond's light qualities. The cut of a diamond is the approach to and results of cutting the raw, rough diamond into the polished, shining stone.
Depth The depth of a diamond is the measure from a diamond's table, or top, to its culet, or bottom. This measure is taken in millimeters.
Depth Percentage A diamond's depth percentage is a measure of a diamond's depth divided by the average width, or diameter, at the diamond's girdle.
Diamond The hardest substance on earth, the diamond is a carbon based crystalline mineral.Its hardness and light properties arise from its "cubic" or "isometric" crystalline from. This form also allows the diamond to be fractured or cut into attractive gemstone shapes.
Diamond Cutting This is the actual cutting of the diamond into its final shape. It is dependent on the skill of the cutter and the inherent qualities of the rough stone. The main goal is to create the most attractive diamond possible while minimizing the loss of rough stone.
Facet Facets are the flat, polished planes that cover the surface of a diamond.Facets act as mirrors and windows on and into the diamond.
Faceted Girdle Cutters will sometimes polish facets onto the actual girdle of the diamond. This allows the girdle to reflect and refract light.
Fancy Diamond Fancy diamond refers to an attractive, strong color property of a particular diamond.A diamond that has a particularly distinctive color, such as red, blue, strong yellow or other will be considered a Fancy Diamond.
Feathers These are inclusions, or imperfections within a diamond. They are cleavages or cracks, usually due to stress, that appear to be clear or white feathers when viewed through a 10x loupe.
Finish The final cut and polish given to a diamond and the overall quality of the diamond's symmetry.
Flaw This refers to an imperfection (such as a knot, feather or carbon spot, among others) found somewhere within or on a diamond.
Fluorescence The effect of ultraviolet (UV) light on boron atoms that are found within some diamonds.Boron within the crystalline lattice structure of the diamond emits a glowing and (normally) bluish light under UV-rich light. This has little to no discernable affect on the diamond's light display.
Fracture A fracture is a break in the diamond's crystal matrix.This occurs when a break occurs that goes against a diamond's natural cleavage plane.
GIA The Gemological Institute of America, GIA, is the world's leading and most respected gemological laboratory. They offer certification for individual diamonds based on scientifically rigorous grading systems.
Hue Hue is a designation of the dominant wavelength of light (also known as color) found in a diamond, such as red, blue, yellow and so forth. Hue is one of the primary indicators in fancy color grading, along with saturation.
Included Crystal An internal flaw, or inclusion, within the diamond crystal. This is a separate crystal within the diamond crystal matrix.It is often simply another diamond crystal.
Inclusion A flaw that is found within the diamond. This can be a break, feather, carbon spot, included crystal or any other imperfection.Inclusions serve as a fingerprint for a diamond, as no two diamonds have identical inclusions.
Internal Graining The result of irregular crystallization growth within the diamond during the diamond's formation.If clear, it will not detract from the diamond's light properties but if colored or dark, it will cause the light transmission to suffer and lower overall clarity grade.
Irradiated Diamond This is a diamond that has been submitted to radiation. This is a process used by some companies on color diamonds in order to increase the diamond's color intensity.
Knot A flaw that is a diamond crystal, essentially a far smaller diamond, which sits on the surface of the diamond. They often appear as small bumps, with a growth pattern that differs from the lines of the host diamond.
Laser-drill Holes They resemble trails of clear thread, and can often be difficult to see. The result of a laser being used to remove an inclusion spot, such as an included mineral.
Loupe A magnifying lens set at 10X magnification and corrected for color. This is the jewelry industry standard for viewing diamonds.
Melee Refers to small, brilliant cut diamonds, normally no larger than .20 carat, or 20 points. Often used as side stones and for pave settings.
Naturals Portions of the original rough diamond's surface that are left unfinished or unpolished in order to save diamond weight during the cutting process. They do not detract from the clarity grade if they are left only on the girdle.
Needle Thin, rod-like included crystals found within some diamonds.
Pave (pronounced PAH-VEY) Taken from the French for "to pave". The pave setting is often used to create the look of a path leading up to a single, central diamond through a quantity of tiny diamonds clustered together along the band.
Pavilion The pavilion is the bottom portion of the diamond. It extends from the widest section (or girdle), to the bottom (or culet).
Pinpoints One of the most common of inclusions, a pinpoint is a clear or white spot that occurs within the diamond during its formation. These are tiny crystalline growths.
Pit Tiny holes, often appearing as white dots, on the surface of the diamond. Smaller pits can be polished away, but larger pits on the diamond's table may require re-cutting, causing the diamond to lose weight.
Point The term "point" is used in the diamond industry to indicate diamond measurements that are lower than one carat. The carat is divided into 100 points, so '50 points' is another way of saying 'half-carat' or 0.50 carats.
Polish The finished polish on a diamond's surfaces, or facets.The facets must have a good polish, free from cutting and grinding marks, in order to most effectively reflect and refract light that passes over and through the diamond.
Rough Girdle This is a girdle that has not been polished or faceted during the cutting process. Can appear rough or even bearded.
Saturation Saturation is the intensity of a particular color in a fancy diamond. The actual color itself is the hue, such as red, while saturation is the intensity of that color, such as how dark or light the red is.
Scratch Scratches on the surface of the diamond that can appear as thin, white lines, shallow in depth and narrow in width. Can detract from a diamond's grade, but can usually be polished away.
Semi-mount A setting that does not include the center stone. The semi-mount can have the side stones present, but the center stone is absent.
Step Cut A diamond cut with long, rectangular facets, which run parallel to the girdle. The emerald cut and Asscher cuts are good examples of the step cut diamond.
Surface Graining Often appearing as parallel lines on the diamond's surface. Similar to polishing lines, and may be the result of irregularities in the diamond's crystal growth.
Symmetry Refers to the placement of a diamond's facets. The facets should all be the proper size in relation to one another, and the proper number.Good symmetry provides the dazzling light display that we know as "scintillation".
Table The largest facet of the diamond. This is the facet that sits at the top of the diamond, and serves as the main entrance and exit point for light.
Table Percentage This is the table's width expressed as a comparison with the diamond's widest point (girdle).
Treated Diamonds Diamonds that have had their color or clarity enhanced beyond the cutting and polishing stage.Includes subjecting the diamond to radiation.
Twinning wisp Lines or groupings of inclusions from the diamond's center that have twisted together to form a single ribbon-like band of inclusion. More commonly found in fancy cut diamonds, and formed as the crystal is growing.
