Cultured pearl Cultured pearl A cultured pearl is a pearl created by an oyster farmer under controlled conditions. Cultured pearls can be farmed using two very different groups of bivalve mollusk: the freshwater river mussels, and the saltwater pearl oysters. A pearl is formed when the mantle tissue is injured by a parasite, an attack of a fish or another event that damages the external fragile rim of the shell of a mollusk shell bivalve or gastropod. In response, the mantle tissue of the mollusk secretes nacre into the pearl sac, a cyst that forms during the healing process. Chemically speaking, this
The Pearl of Death when caught the pearl is not found on him and he is released. Later, Holmes hears of an apparently motiveless murder. An elderly colonel is found with his back broken amid a pile of smashed china. Holmes takes an immediate interest in the case as the unusual method of killing is that of "The Hoxton Creeper" (Rondo Hatton), known to be Conover's right-hand man. Another murder occurs, of a little old lady, also surrounded by smashed china. Conover makes two attempts to kill Holmes, who surmises that Conover is desperately trying to recover the stolen pearl. After a third killing