The Definition of a Pearl

The definition of a pearl comes from a short article written in 1907. The Pearl is a small roundish body, found in the shells of certain mollusks, such as oysters. Pearls are secreted by the mantle of the animal. They are caused by the presence of some irritating body, as a grain of sand. The pearl is formed by a secretion which hardens over the sand and makes it less irritating, and if this projection breaks loose and becomes rounded or pear-shaped, it is valued as a pearl for jewelry. Pearls are not found in all oysters, and a perfect one is a rare occurrence. In color they are white, black or pink, and they reflect the light in a beautiful play of colors.

The most valuable pearls come from the large oysters found most abundantly in the Persian Gulf and off the west coast of Mexico. In the Persian Gulf the fishing is done from a boat, which is accompanied by five pairs of native divers. One goes to the bottom, pulled down by a heavy weight which he carries. His partner watches from the boat the cord attached to the diver; at the proper signal the man in the boat draws up the weight, then the oysters and lastly the diver. Then the oysters are carried to the shore and laid in piles, where they remain until they become throughly decomposed; then they are thrown into sea water and carefully examined for pearls, while the shells are cleaned and split into layers for the mother-of-pearl which they contain.

The pearl fisheries of Ceylon are a government monopoly, but the revenue derived from them is not a regular one, the fishery sometimes failing for years in succession. There was no fishery, for example, between 1837 and 1864 or between 1863 and 1874. The pearl oyster occurs throughout the Pacific. Very fine pearls are obtained from the Sulu Archipelago, northeast of Borneo. Of late years pearl fishing has been started with considerable success is Austrailian seas; and it is carried on also in the Gulf of Mexico, upon the coast of California and in the vicinity of Panama.

Pearls have formed valued articles of decoration and ornament from the earliest times. Julius Ceasar presented Servilia, the mother of Marcus Brutus, with a pearl valued at the modern computation of $240,000 (1907 dollars), while Cleopatra was said to have swallowed one gem valued at $300,000 or $400,000 (1907 dollars). The "pilgrim" pearl of Moscow is diaphanous in character and weighs 24 carats and again is highly valuable.

Artificial pearls are largely make in France, Germany and Italy. They are very well imitated by the scales of certain fishes. A Substitute for black pearls is found in close-grained hematite, not too highly polished, and pink pearls are imitated by turning small spheres out of the rosy part of the conch shell.