Production of cultured pearls

Abstract

Pearls are among the gems of the sea and have formed a valuable itern of jewrllery through the ages. Like the precious corals, they are produced by the metabolism of living animals. The pearl oysters (Pinctada maxima, P. fucata, P. margaritifera and others), wing-sliell (Pteria penguin) and the abalone (Haliotis discus) living in the sea bottom, and the limnetic mussels (Hyriopsis schlegeli and Cristaria plicata) are the well- known pearl-producing molluscs. Pearls produced by Pinctada spp. are highly valued in the gem trade.