The pearl was one of the first gems to be valued by people. Humans collected pearls because they believed that the gems have mythical powers: health, eternal youth, and vitality, among others. Most pearls are now cultured, is the result of human intervention.

Pearls are organic gems. Pearls are produced by mollusks, and can be one-shelled or two shelled. Only some mollusks can produce pearls. Pearl-producing mollusks can live in freshwater or salt water.