Coated Natural genuine calcium carbonate CaC03 calcite in minute crystalline form, which has been deposited in layers. Nacreous and iridescent. Harvested and cut from the giant clam (Tridacna gigas), the largest living bivalve mollusk in existence that can weigh more than 200 kilograms (440 lb), measure as much as 120 cm (47 in) across. The shell nucleus is the same nucleus as used as the seed or nucleus for South Sea Pearls. The nucleus is carefully cut and polished to achieve a near perfect shape then coated for a final finish providing a near perfect â€œskinâ€ and â€œlustreâ€. The finished Pearl is a result of a long process of shaping and coating, and intensive quality control inspection. The Coated South Sea Pearl Pearl will always keep its shine and color, and will not be affected by sweat, Perfume or detergents.