gems, gems general

Stoddard’s brief review summarizes United States production and trade in gems and precious stones during 1921 and provides notes on several materials of contemporary interest. Domestic production was valued at $518,280, a sharp increase over $265,205 in 1920, with Montana overwhelmingly dominant at $489,021; Arkansas diamond production was not reported. Considerable attention is given to distinguishing diamond from quartz and other colorless gems by crystal form, hardness, cleavage, specific gravity, and optical properties. Topaz is discussed both mineralogically and in relation to the misleading trade names “Indian,” “Bohemian,” “Spanish,” and “Saxon” topaz applied to yellow quartz. Sapphire production at Utica, Montana, increased through washing accumulated mine material, whereas virtually no work was carried out at the Rainbow Ridge opal property in Virgin Valley, Nevada. The report also notes “cuprous gem,” a mixture of chalcocite and chrysocolla from Washington, and the cutting of green manganosite from Franklin Furnace, New Jersey. Tables summarize U.S. production from 1917–1921 and imports of diamonds, pearls, and other precious stones.