Freshwater pearls include all types of pearls found in river mussels or freshwater lake mussels. Some varieties of mussels can receive up to 60 pearl grafts at a time. These pearls vary between 1mm (seed pearls) and 30 mm for very large baroque pearls. Several forms of freshwater pearls are available on the market such as: round, semi-round, potato, button, semi-baroque, baroque, keshi, fireball, as well as certain forms grown using preformed cores such as pellets, hearts, stars or flowers. These pearls are found in white, cream to slightly silvery, to a wide variety of shades of pink, purplish and coral. China is by far the largest producer of freshwater pearls, although there is also production on a much smaller scale in Japan, the United States and Vietnam, among others.
Saltwater cultured pearls from the Akoya oyster Pinctada fucata martensii. These pearls are typically round, ranging from very pale pink to white, more or less pronounced shades of cream, and rarely bluish gray. On the market, we find mostly Akoya pearls between 6 and 8 mm although they exist between 4 and 9 mm and exceptionally up to 11 mm. Japan is the largest producer of Akoya pearls, but Hong Kong, South Korea, Vietnam and Sri Lanka also produce smaller quantities. The term "Japanese pearl" usually refers to this type of pearl.
South seas pearls
In general, this term refers to all saltwater pearls produced in the region between the Philippines, Indonesia, Australia and French Polynesia. However, the pearls of the South Seas are mainly pearls from the oyster Pinctada maxima. You may also hear the expression Gold-lipped oyster or White-lipped oyster to describe this same mollusc. These pearls are usually large (between 8 and 19 mm) and vary in color from white to silvery white to gray and golden white to brilliant gold. The main producing countries are Burma and Australia.
Also known as black pearls, Tahitian pearls exist in a wide variety of natural colors, from very light gray (sometimes even white) to very dark gray, passing through a wide variety of colored highlights: green, golden, coppery, bluish, pink or purplish. These pearls are derived from the oyster Pinctada margaritifera and as the name suggests, are mainly found in French Polynesia. They are usually between 8 and 18 mm, but more frequently are between 9 and 12 mm. Although we are seeing Tahitian pearls on the market between 6 and 8 mm, these sizes are still rare and marginal.