Black Pearl Quality
This is determined by observing the special features of the pearl's surface and luster. Special surface features are considered to be any flaw in the nacre that is visible to the naked eye such as pits, bumps, scratches, deposits, ridges and cracks.
Luster is evaluated according to reflection of light on the pearl's surface. The brighter the reflection, the higher the luster.
Black cultured pearls are defined by four basic qualities: A, B, C, D.
Quality A
An "A Quality" pearl is one that has no surface flaws or very slight flaws that are visible to the naked eye and confined to less than 10% of its
surface. All "A Quality" pearls exhibit a very high luster.
Quality B
A "B Quality" pearl is one that exhibits high or medium luster with some flaws visible to the naked eye and distributed over less than one third
of the surface.
Quality C
A "C Quality" pearl is one that exhibits several visible flaws, distributed over more than one third of the surface and exhibits a medium quality
luster.
Quality D
A "D Quality," pearl is one that exhibits a large amount of visible flaws over more than two thirds of the surface, regardless of luster.