South Sea cultured pearls are pearl concretions that are secreted inside the silver- or gold-lipped Pinctada maxima species of pearl oysters cultivated mainly in Australia, Papua New Guinea, Indonesia, the Philippines, Thailand, and Myanmar (Burma).

There is no standard South Sea pearl grading standard and each individual company has its own standards. The South Sea Pearl Consortium, the trade association of South Sea Pearl farmers and distributors, uses five grading standards. Pearl Oasis uses those five standards, plus a sixth, nacre thickness. The following is the standard that we uses.

Six Pearl Grading Factors

There are six pearl grading factors we use to grade South Sea pearls:

1. Pearl Shape: Round, Semi-Round, Semi-Baroque, Ringed or Circle, Baroque.
2. Pearl Size: 8MM to 18MM.
3. Pearl Surface Quality: Clean (A), Light Blemished (B), Moderately Blemished (C), Heavily Blemished (D).
4. Pearl Luster: Very high (AAA), High (AA), Medium (A), Soft (B).
5. Pearl Nacre Thickness: Thick, Thin.
6. Pearl Color: Body color plus overtone.