gems, gems general

A comprehensive review of precious-stone production, mining, discoveries, and trade during 1909. Sterrett records a marked increase in U.S. gem production, especially turquoise, variscite, tourmaline, and chrysoprase, reflecting the growing popularity of blue and green matrix stones; more than 17 tons of rough turquoise and 3½ tons of variscite were mined during the year. A major portion of the report is devoted to detailed descriptions of American deposits, including turquoise and variscite in Nevada and Utah, a new emerald occurrence near Shelby, North Carolina, Montana sapphires, California tourmaline and californite, and numerous agate, amethyst, beryl, opal, garnet, and ornamental-stone localities. Particularly important is an extensive account of the newly discovered benitoite deposit in San Benito County, California, covering its geology, paragenesis with natrolite and neptunite, crystallography, optical properties, cutting, and gem qualities. The report also describes the newly named rose-colored beryl morganite from Madagascar. Diamond sections survey Arkansas, California, South Africa, German Southwest Africa, British Guiana, and Australia, while Burmese ruby mining at Mogok and sapphire production in Queensland and Ceylon are also discussed. The report concludes with U.S. production statistics and notes a strong recovery in precious-stone imports, especially rough and cut diamonds, indicating a return of the diamond trade toward pre-1908 conditions.