Читать книгу The Book of the Pearl. The history, art, science, and industry of the queen of gems онлайн

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Several varieties of Margaritifera margaritifera are recognized. The type species occurs along the north coast of Australia, from Brisbane on the east to Sharks Bay on the west; on the New Guinea coast; at Formosa; and about many of the islands of the Pacific. The well-known “black lip shell” of Australian waters is of this species; it shows a greenish black on the margin of the nacre. The yield of this is very small compared with that of the large pearl-oyster of Australia.

SHELL OF PEARL-OYSTER WITH ATTACHED PEARL

(Margaritifera margaritifera mazatlanica) From Costa Rica

The Margaritifera margaritifera occurs on the eastern coast of Arabia in two varieties, which differ somewhat from the type species. These have been designated by Jameson as M. margaritifera persica and M. margaritifera erythræensis. These are much larger than the Lingah shell of the Persian Gulf, but are smaller than the Australian species. The percentage of pearls in them is less than in the Lingah species, but from a commercial point of view this is to some extent offset by the greater value of the shell. The M. m. persica is more numerous in the gulf than the M. m. erythræensis, and large quantities of the shell are marketed in Europe. Formerly the shipments were made principally by way of Bombay, hence the shell is known in the mother-of-pearl trade as “Bombay shell.” The exterior is of a light grayish or greenish brown color, with yellowish white radial bands. The nacre has a slightly roseate tint, and the margin is greenish yellow. The pearls found herein are more yellowish in color and attain a larger size than those from the Lingah oyster.