It's no accident that Cancer's birthstone, the pearl, bears a resemblance to Cancer's ruling planet , the moon. The watery sign of Cancer and the pearl enjoy an intimate association with the sea and the many cross cultural incarnations of the mother Goddesses - Isis, Diana, Neptune and Aphrodite.
Pearls generate a protective nurturing and maternal energy. Their promotion of love and marital happiness corresponds to the inclusion of pearls in traditional bridal wear, in strands worn on the neck or wrist, in earrings, on the tiara or bridal cap, and on the dress itself. Lovers of water and aquatic recreation by and large, Cancerians will appreciate the South Pacific tradition of wearing or carrying a pearl to ward off shark attacks.
Pearls also ensure domestic harmony by protecting family heath, preventing house fires and promoting fertility and longevity. The varied shades and colours of peals reflect the shifting moods of Cancer. These traits in turn correspond to the various phases of the moon. Black or blue pearls are worn as good luck charms. Yellow pearls invite material good fortune. Red pearls enhance intellectual abilities and pink pearls bring the comforts of the good life.