Overview:The pearl—the only gem produced by a living animal—has long carried a certain allure. Yet the best mollusk for making this gem—the pearl oyster—doesn't always produce a pearl, and even then, the pearls are rarely perfectly round. It wasn't until the late nineteenth century, when a Japanese scientist discovered a technique to incite oysters to produce these gems, that an industry was formed. Inducing an oyster to create a pearl is only half the battle—the oyster then needs a nutrient-rich, open environment in which to grow. This NOVA program looks at the science of pearl farming, follows efforts of oyster farmers trying to cope with growing problems of pollution and overcrowding, and considers the shifting sands of dominance within the pearl industry.