Pearl or parasite enters a bivalve mollusk and settles inside the shell. The mollusk, irritated by the intruder, forms a pearl sac of external mantle tissue cells and secretes the calcium carbonate and conchiolin to cover the irritant. This secretion process is repeated many times, thus producing a pearl. Natural pearls come in many shapes, with perfectly round ones being comparatively rare. Typically, the build-up of a natural pearl consists of a brown central zone formed by columnar calcium carbonate (usually calcite, sometimes columnar aragonite) and a yellowish to white outer zone consisting of nacre (tabular aragonite). In a pearl cross-section
Pearl of Kuwait Pearl of Kuwait The Pearl of Kuwait is a pearl that was bought in 2004 by its current owners, Bond Street, London jewellers Symbolic & Chase, and named the "Pearl of Kuwait" in recognition of the Persian Gulf waters in which many pearls have been found. It measures 258.12 grains (64.5 carats, 69.8 carats with its diamond cap) making it the third-largest (documented) well-formed natural pearl drop. In 2004, a large pearl named the Pearl of Kuwait was consigned by an undisclosed private family for auction at Christie's in London. The Pearl of Kuwait was part of the Pearls exhibition