Pearls can be of three types, cultured, fresh water, and south sea. Pearls are classified by origin, then graded by size, shape, nacre thickness, color, luster, and surface clarity. Pearls are assigned quality standards of grade A, AA, and AAA. Triple A is considered the finest quality. All pearls come from oysters of various varieties which can influence there color and sizes. Japan is the leading producer of salt water cultured pearls which tend to be round in shape and color. South Sea pearls originates in Australia, Indonesia, Burma, and the Philippines. They are prized for there black colors, large sizes, and beautiful hues of peacock . Care must be taken while wearing pearls, as water, lotions and perfumes can alter the nacre. Pearls have a long tradition of classic elegance. It is the birthstone of June and astrological sign Cancer.