Welcome the opportunity to free another neural region of a little detritus.DWhatley;178505 said:Now that you have freed that piece of memory for other knowledge, how do they seed cultured pearls?
The process stolen and thereafter perfected/patented by Koichi Mikimoto in the early 20th century involves surgical creation of a pearl sac by inserting a small piece of mantle tissue into the flesh of the animal (grafting), thus assuring that a cyst is formed of mantle epithelial cells producing the same aragonite microstructure as the inner lining of the shell (most commercially: nacre/mother of pearl). The primary objective is round shape, so uncommonly found in nature. To guide the shape and guarantee pearl size, a round shell bead is introduced at the same time as the mantle tissue. The bead is then coated with the shell material, resulting in an inverted shell (exterior within, interior without). Eventually it was discovered that insertion into the oyster's gonad would doubly assure that the sac would become round, the gonad also serving as a less surgically-sensitive organ.
The success of this model literally destroyed the natural pearl business by the mid-20th century (not to ignore overfishing by a new generation of pearl divers with air supply), as women could obtain perfectly round and shiny 'pearls' at a tiny fraction of the price Indian Rajahs and robber-baron matrons traditionally paid for the real thing. But in the end, such 'pearls' are nothing more nor less than nacre-coated beads in the eyes of the purist.
Mantle tissue without the guiding bead is also done, typically resulting in baroque pearls known as keshi, although the Chinese freshwater mussel pearl industry has perfected its grafting technique to the point that the bead is no longer necessary to obtain symmetrical shape.