Saltwater pearls are grown in ocean coastal waters of Japan, China, Tahiti, and South Sea areas. They are considered high class pearls for their exceptional beauty and high luster. Saltwater pearls include classic Akoya pearls, large exotic black Tahitian pearls and luxurious golden or white South Sea pearls. Akoya oysters (Pinctada Fukata) produce akoya pearls. Large Silver-lipped oysters ( Pinctada Maxima) produce white South Sea pearls. Large Black Lipped oyster (Pinctada Margaritifera) produce black Tahitian pearls. Large Gold-Lipped oyster (Pinctada Maxima) produce golden South Sea pearls. Ocean salt waters have more minerals and nutritious particles than freshwaters; therefore saltwater cultured pearls have higher luster and more beautiful nacre than freshwater pearls. The successful production rate for saltwater pearls is much lower than freshwater pearls. That is why saltwater pearls demand a higher price in the market. Less than 5 in 10 will survive the nucleation process. Of the survivors, about 40% will successfully encircle the shell nucleus irritant with nacre. Overall, less than 5% of pearl output can be considered "high quality." The most desirable shape for saltwater pearls is round. The most popular colors for saltwater pearls are white, cream, golden and black. Saltwater pearl market occupies 75% of all pearl market today. Saltwater pearls are graded on a scale from AAA (Excellent) - Commercial (Poor) grades. Below is a saltwater grading chart with explanations.

AAA - Perfectly Round; Excellent Luster; Clean Nacre of 95% Inclusion Free Surface; Excellent Matching; Top 1%.
AA+ - Visibly Round; Excellent Luster; Clean Nacre of 90-95% Inclusion Free Surface; Excellent Matching; Top 5%.
AA - Off Round; Good Luster, Good Nacre of 80-90% Inclusion Free Surface; Good Matching; Top 15%.
A/A+ - Off Round to Baroque ; Moderate Luster; Medium Nacre of 70% Inclusion Free Surface; Moderate Matching.
A - Very Off Round to Baroque ; Moderate/Low Luster; Moderate to Heavily Blemished Nacre; Moderate Matching.
Commercial - Asymmetrical Baroque; Moderate/Low Luster; Heavily Blemished Nacre; Heavy Inclusions; Poor Matching.