Diamond has total internal refraction so to maximise its brilliance the cut is extremely important. If the cut is done well the stone has a wonderful lustre. If done badly, even the best diamond will look flat, dull or even “fish-eye”. A term used when the cut is too shallow.
GIA Classification of cuts read as follows:
Excellent
Very Good
Good
Fair
Poor
For more detailed information please go to the official GIA website.
