Cut, Clarity, Color, Carat Weight and Fluorescence of Diamonds
CUT refers to the shape or design of a Diamond and to its proportions and finish, e.g. round (also referred to as brilliant), pear, heart, oval, etc. Often for identification a trade term is used to denote cut, such as emerald, marquise, TrillionTM (a patented triangular brilliant cut Diamond). A plot of the Diamond on the appraisal report will illustrate the cut. The cut is analyzed considering proportions and symmetry, through the use of instruments and visual techniques, for deviations from the standard parameters for table diameter, crown angle, girdle thickness, pavilion depth, culet size and/or centering, roundness and finish.
CLARITY GUIDE is based upon the size, nature, number, color, and position of inclusions and blemishes. Inclusions penetrate or are contained within the Diamond, while blemishes are confined to the surface (such as a nick, scratch, or abrasion). Clarity is graded through a binocular microscope at 10 power. The internal and external characteristics of the Diamond are illustrated on the Diamond plot. The Gemological Institute of America clarity grading system has been used. The following illustrates the range of clarity from flawless to imperfect:
COLOR GRADE is based upon the amount of color the Diamond exhibits compared to a set of master color Diamonds, which have been color graded and registered as a set by the Gem Trade Laboratory of the Gemological Institute of America. Color grading is subjective and is done under the equivalent of undistorted natural daylight. The GIA color grading scale ranges from D (colorless) to Z (fancy yellow) as follows:
CARAT weight is indicated to the nearest thousandth.
FLUORESCENCE is a characteristic of many Diamonds and generally does not affect the color grade. Diamonds are checked for fluorescence using a long wave ultraviolet light source. Should the Diamond fluoresce when exposed to this light, the color and relative intensity of that color is recorded. Should the nature of the fluorescence enhance or detract from the color of the Diamond in daylight, then comments to that effect will appear in the appraisal report.