WIld pearls only form in about one in a thousand oysters so cultured or farmed pearls from pearl oysters make up the most of those that are currently sold. The formation of a natural pearl is the oyster's defence mechanism to an irritant that enters the shell. If the irritant (e.g. a piece of sand, larva or parasite) picks up a a piece of the mantle tissue on the way a pearl can form (see next page)
industry in Australia is based on the silver lipped pearl oyster (Pinctada maxima), which
produces high quality cultured pearls known as South Sea pearls. These pearls are white in colour, with a brilliant shine. Pearls are sold for use in jewellery especially necklaces.
This species is found across the central Indian and Pacific Ocean region from India to New
Guinea and the Philippines, and, in Australia, from Carnarvon in Western Australia to
south of Cairns in Queensland.