As this chart demonstrates, diamond clarity ratings range from FL (flawless) to I3 (heavily included).
Gem-grade diamonds are given a clarity rating based on a scale that is standard in the trade. However, when Tiffany believes that a diamond’s clarity is on the borderline between two grades, Tiffany will always give the stone the lower grade.
internally flawless—minor surface blemishes
very, very slightly included
very slightly included
Tiffany gemological standards refer only to round brilliant diamonds from .18 to 2.99 carats set in certain ring styles. Round brilliant diamonds smaller or larger, fancy shape diamonds and fancy color diamonds each have their own specially tailored standards of evaluation. Consult your Tiffany Sales Professional for details.