POLISH
The level of smoothness from surface defects created from polishing. Excellent to good grades or not visible to the naked eye. Only severe defects may affect light patterns as light rays enter and exit the diamond.
Excellent
Very good
Good
SYMMETRY
The alignment and intersections of the facets on the diamond. Symmetry can affect the diamond’s brilliance as it may redirect light rays.
Excellent
Very good
Good
Fluorescence
Diamonds may emit blue light when exposed to UV rays. The presence of fluorescence will not affect the colour in a major way as other factors.
None
Faint
Medium
Strong
Very Strong
TABLE
The largest flat facet when viewed from the top of the diamond measured in percentage. The table refracts light rays entering through the pavilion angle to the observer. Table % is calculated by dividing the table diameter by the average girdle diameter.
DEPTH
The depth % is the distance between the culet and table. It is calculated by dividing the width of the diamond by the depth and is measured in percentage. Depth proportions can affect the brilliance of the diamond due to light ray angles reflected within the diamond.
