The penguin’s wing oyster is a species of marine bivalve mollusc in the family Pteriidae, the pearl oysters. It is native to the western and central Indo-Pacific region and is used for the production of cultured pearls. It is found attached by its byssal threads to a number of different substrates but typically to hydroids, at depths of less than about 25 m. Wild oysters of this species seldom contain pearls.
Archer’s badge of polished oyster shell, bearing an incised cartouche containing the prenomen of Senusret I (Kheperkara). Middle Kingdom, 12th Dynasty, ca. 1956-1911 BC. Now in the Kelvingrove Art Gallery and Museum, Glasgow.
This is a chart of what percentages of pearls actually make is to the pearl auctions. Only 55% of the oysters implanted with a pearl seed (nuclei) and put out in the farm actually survive to the stage the pearls are extracted.
Only one third of the total oysters produce marketable pearls, with the other 22% either not covering the nuclei enough, or are shaped abnormally/unevenly to be able to sell.