What is Mother-of-Pearl?
Mother-of-pearl is the lustrous interior layer of a mollusk shells, such as oysters. Also known as nacre, it is a calcium carbonate, it is the same material as pearls.
The shells used to make counters came from the large saltwater pearl oyster (Aricula margaritifera or Meleagrina margaritifera). Not found in Chinese waters, the shells were imported into China from the Red Sea, the Persian Gulf, the India Ocean, and the South China Sea.[i]
[i] “Articles of Import and Export of Canton” in The Chinese Repository (Canton, 1834), volume II, p. 434; Grove Encyclopedia of Decorative Arts (Oxford: Oxford University Press, 2006), volume II p. 129; William Milburn, Oriental Commerce; Containing a Geographical Description of the Principle Places in the East Indies, China, and Japan (London: Black, Parry & Co., 1813), Volume II, p. 464