Two grading systems are in use: ‘AAA-A Grade System’ and ‘A-D Grade System’ – additionally referred to as Tahitian grade system. They’re the most universally accepted systems, as well as are utilized by almost all reputable wholesale and retail pearl dealers.
AAA-A Pearl Grade System
The system will grade pearls upon a scale from AAA – A, with AAA being of the highest grade, the grade scale is typical to akoya and freshwater pearls only, yet is accepted by most Tahitian and South Sea pearl dealers. The AAA – A grades will be as follows:
AAA: A virtually flawless pearl. The surface luster is extremely high, and 95 percent of surface is going to be free from defects.
AA: Surface has an extremely high luster, and at the minimum of 75 percent of the surface is going to be free from defects.
A: Lowest jewelry grade pearl that has low surface luster and/or over 25 percent of its surface displaying defects.
A-D Pearl Grade System
This grade system will grade pearls upon a scale from A – D, with A being of the highest grade. The system is utilized in French Polynesia in order to grade South Sea and Tahitian pearls only. It’s why it’s called the ‘Tahitian system.’ As the system is standard within producing countries, additional marketplaces will utilize the AAA-A System.
A: The highest-quality pearl, extremely high luster and just minor imperfections over fewer than 10 percent of the surface.
B: Medium or high luster. Surface might possess a few imperfections over no more than 30 percent of the surface area.
C: Medium luster that has surface defects over no more than 60 percent of its surface area.
D: Might possess many small defects over 60 percent of surface or deep defects over not more than 60 percent of its surface.
‘D’ Pearls might have a blend of deep and minor defects over not more than 60 percent of the surface. Within this pearl grade, the luster will be irrelevant. Even the most lustrous of pearls are going to be graded ‘D’ if the surface area is blemished to this extent.
Pearls under ‘D’ grade are considered unacceptable for usage in jewelry.