<p style="text-align: justify;">Birthstone for June, pearls have been widely used for personal ornament since prehistoric times. Pearls are formed in molluscs as a natural defence to prevent their soft bodies from being harmed by foreign irritants. In an effort to ease such irritants, the body of the mollusc takes defensive action. It begins to secrete a smooth, hard crystalline substance around the irritant. This substance is called nacre. As long as the irritant remains within its body, the mollusc will continue to secrete layers of nacre and the result is a pearl. A natural pearl begins its life as a foreign object, such as a parasite or piece of sand that by accident lodges itself in the oyster’s soft inner body. The pearl is found by chance when the shell is opened. Since the advent of cultured pearl production, fishing for natural pearls has diminished. Cultured pearls are created artificially by the introduction of a small mother of pearl bead into the interior of the mantle of a live oyster. Freshwater pearls can be found in bays and rivers throughout the world. They are harvested from freshwater molluscs. Freshwater pearls can be non-nucleated, which means that man has not inserted a tiny bead into the mussel for the pearl to form around or they can be cultured in the same way as saltwater pearls. Pearls produced in oysters off the coast of Japan, Australia and in the South Seas can be white, white rose, white green, cream, gold and blue-grey in colour. Large pearls cultivated in Tahitian waters are often black in colour. Freshwater pearls are available in a wide range of colours Pearls can be dyed as they are forming or after they have been harvested. The five main factors which determine the value of a pearl are lustre, surface quality, shape, size and colour. Because pearls are organic in origin, they are relatively soft compared to other gemstones and precious metals. Always put pearls on over clothing, after applying perfumes and cosmetics. Contact should also be avoided with hair spray, acidic perspiration, bleach and swimming pools. Remove for swimming or bathing because excessive moisture will cause the string on which they are strung to degrade and may affect the glue used to affix them to earring posts. Pearls should be restrung every three years or annually with heavy wear. Individual knotting will prevent all the pearls in a strand from falling off should a break occur. Knotting also prevents the pearls from rubbing against each other.</p>