Cultured Pearl Types

Cultured pearl types fall into two broad categories: those produced in saltwater and those produced in freshwater. The overwhelming majority of whole pearls grown in saltwater are cultured by essentially the same process, which is called bead nucleation. Pearl farmers implant the host mollusk’s gonad with a bead nucleus fashioned from a freshwater mussel shell along with a tiny piece of mantle tissue from a donor mollusk. They nurture the host mollusks for varying periods of time and then harvest their cultured pearl products.

Virtually all freshwater pearl culture differs from saltwater pearl culture in two important ways. First, the implantation takes place in the mantle instead of the gonad. Also, for the great majority of freshwater pearls, there’s no bead involved. Farmers implant only tissue pieces, and usually in greater numbers than the beads and tissue pieces used in saltwater culturing. The process is called tissue nucleation. 

Cultured pearls without bead cores consist mainly of aragonite and conchiolin, and their construction is essentially the same as natural pearls. Cultured pearls with bead cores consist of those same substances, but they’re deposited on beads made from freshwater mussel shells.

There’s much more detail about the culturing processes for each major pearl type in the assignments to come.

Harold & Erica Van Pelt, earrings courtesy of Mastoloni, New York; South Sea strand (9–12 mm) courtesy of The Collector Fine Jewelry, Fallbrook, California
Since the early 1990s, the cultured pearl industry has expanded to include many types and sources. These include akoya (bottom two rows), Tahitian (top two rows), Chinese freshwater (third row), and South Sea types. The earrings are set with diamonds and Tahitian cultured pearls.