Man has been intrigued by the origin of pearls, sensitive to their beauty, and convinced of their medicinal value for at least 5 cent. A mixture of folklore and observation preceded the earliest scientific inquiries. Fishing and trade commenced in S. Asia, between India and Sri Lanka and around the Persian Gulf. In W. and Central Europe, Inner Asia and China, and N. Amer. Freshwater pearls were probably known and treasured before those of marine origin. A refined nomenclature points to a long familiarity with etymologically related words for ‘pearl’. Pearls were prominent among the luxury products of world trade and were high among the objectives of expeditions to the eastern and western Tropics. Illustrations.