waters off the coasts of equatorial South. America, the West Indies, Panama, and southern California. The Aztec kings possessed pearls of great beauty and price, obtained, it is supposed, from Panama. The palace of Montezuma, when despoiled by the Spaniards, is described as "studded with pearls," along with emeralds.
Some fine pearls are produced in inland waters by the freshwater mussel (Unio margaritifera). Most of the river pearls are found in China, though at some periods the pearl industries in England and Scotland have been important. The rivers of Germany and parts of Russia are also pearl-producing. The principal river-pearl fishery in the United States is in the Little Miami in Ohio.
The marine mollusks yielding pearls are the Avicula (Meleagrina) margaritifera, Avicula macroptera, and Avicula fucata.
In the Persian Gulf the Avicula fucata is specially fished for gem pearls, as it produces more and of finer quality than the other varieties, though it is smaller and of less value for the mother-of-pearl lining of its shell. All three varieties mentioned, however, are found on the famous Great Pearl Bank, which lies along the west coast of the gulf. There the pearling industry from remote times has so dominated the people that it has passed into a proverb, "All are slaves to one master. Pearl."
The great Ceylon pearl fisheries are now a monopoly, under the supervision of the British Government, as formerly under that of the Portuguese and the Dutch. The fishing seasons occur at irregular and infrequent periods, only half a dozen having been sanctioned by the inspecting officer in the quarter century between 1863 and 1887. The value of the pearls from these several fishings varied from fifty thousand to three hundred thousand dollars, with a total of about one million dollars. The Ceylon fishing season runs from four to six weeks. The latest of which there is data was that of 1889, when in twenty-two days fifty divers brought up eleven million oysters, which yielded the Government fifty thousand dollars and the divers about fifteen thousand dollars. In Ceylon it is the custom to land the cargoes of oysters on the shore to die and decay. When sufficiently decomposed they are opened and then washed and searched for the more valuable loose pearls, after which the boutons are clipped from the shells, and the larger of the shells themselves selected for their mother-of-pearl.
Diving for pearls is perhaps the most perilous of occupations, with the possible exception of its antithesis—that of aeronautics. There are the terrible physical tortures of the first descents from the pressure of water; the bleeding from nostrils, ears and mouth; the bursting of small blood-vessels in the lungs; and the