Generally, the South Sea cultured pearl is the largest pearl on the market. They range in size from 9mm to 20mm, with the majority around 13mm. The Pinctada maxima oyster pruduces these treasures every 20 to 24 months. The South Sea pearl comes in a range of colors from white to yellowish orange. The three most common shapes are round, semi-round and button. South Sea pearls are only grown around the coast of Australia, Indonesia and the Phillipines.