The magnificent, satiny lustre of these fantastic white South Sea is produced by the silver-lipped South Sea oyster. Their subdued opalescence will subtly change in appearance under different light conditions, making them a constant marvel to behold. Harvested in sizes from 9mm and up, their shapes range from round, oval or teardrop to free-form baroque. These pearls are as near to round as possible. Lustre is the amount of light a pearl reflects from both its surface glow and the deep mirror-like reflection of its inner light. The better the nacre quality of the pearl, the more superior its lustre. Only the highest quality pearls with the most luminous lustre carry the Pearl and Bead name. Subtle blemishes and tiny marks are part of a pearl’s natural texture and proof of its genuine origin. These blemishes are the result of sea particles that drift into the oyster and brush against the pearl as it forms. Fewer surface imperfections denote a higher quality, more valuable pearl.Of the many shapes available, perfectly round pearls are the rarest and most valuable. With Pearl and Bead’s South Sea cultured pearls, unique shapes like button, tear drop, oval and baroque are also popular.While size does not affect the quality of cultured pearls, it does affect the price. Large pearls are more difficult to cultivate and their rarity makes them more valuable. Pearls are measured in diameter increments of millimetres (mm). South Sea cultured pearls begin at 8mm and can grow as large as 18mm. These pearls are approximately 12mm to 15mm with an 18ct white gold ball clasp.