BRILLIANCE:
The white light that reflects up through the top of the diamond.
CULET:
The facet on the bottom tip of the diamond. A diamond with no culet has a pointed tip. A diamond with a small to large culet has a flat surface at the tip.
FLUORESCENCE:
A bluish glow that comes from a stone when exposed to ultraviolet light. The effect of fluorescence depends on the combination of the color of the stone in question and the strength of the fluorescence. Faint fluorescence has very little effect on a stone of any color. Medium blue fluorescence and strong blue fluorescence can have a positive effect on stones.
MEASUREMENTS:
Measurements are calculated to the nearest hundredth millimeter and are usually written in this format: length x width x height
FIRE:
The colored light that reflects up through the top of the diamond.
DEPTH:
Depth refers to the height of a diamond from the culet to the table. The depth percentage listed on the certification indicates the height of the diamond relative to the width measurement (height value, width value). A diamond which is too shallow or too deep will disperse light through the sides or the bottom instead of the top facet.
GIRDLE:
The girdle is the narrow belt around the stone, which divides the top portion of the diamond (crown) from the bottom portion of the diamond (pavilion). Girdle is usually expressed as a range, indicating that it may vary from one part of the stone to another. If a girdle has small, flat, polished surfaces on it, it is referred to as "faceted".
POLISH:
Refers to the external finish of the facets. An "good" polish grade reflects the quality of the work the diamond cutter has put into the stone. Symmetry: Graded according to how precisely the facets are aligned (i.e., the top of the facet should mirror the bottom of the facet). A facet that does not have symmetrical sides will negatively affect how light reflects from the stone.
TABLE:
The largest flat surface on the top (crown) of the diamond. The table percentage refers to how much of the total width is occupied by the table. A table that is either too large or too small will negatively affect how Light reflects up from the surface of the stone.
