Everything you need to know about Pearl
One who possesses or wears a good pearl enjoys the blessings of Lakshmi, the goddess of prosperity. This blessed one will live long, become free of evil, and develop vitality and intelligence.
The best pearls are Moonlike, shining white in color, with a perfectly round, globular shape. They should be compact, with high specific gravity, spotless, and free from blemishes. The appearance should be lustrous and smooth. White pearls make good spiritual gifts, the rosy pearls are known for improving intelligence and power while the yellow pearls are known for bringing material prosperity. Black pearls are rare but are not ideal for development. Coppery or non-lustrous, dirty, cracked or otherwise defective pearls should be avoided as they are inauspicious.
Pearls are found in Sri Lanka, India, Persian Gulf, Venezuela, Mexico, and Australia. Australian pearls are generally considered less desirable. Though pearls from Bahrain are highly prized, Sri Lankan pearl stones are considered the best. In India, the best pearls come from the Bay of Bengal and Tuticorin in South India.
Pearls grow inside oysters and rarely elsewhere (bamboo, cobra, conch, etc.). Today, cultured pearls are available which may be distinguished from genuine pearls by the bore, which is uniform in the genuine but thin at the start and wide in the middle in the cultured pearl. Another difference is in the structure, which is concentric in the genuine pearl but parallel in the cultured. Natural pearls are also available.