corundum, treatments.6, gems

A detailed survey of the international precious-stone industry in 1916, emphasizing the continuing effects of the First World War on production, cutting, trade, shipping, and prices. Kunz records exceptionally high U.S. imports of precious stones and pearls, while discussing wartime controls on diamonds, changes in the Amsterdam and Antwerp cutting industries, and the growing importance of American and British cutting. Much of the report concerns diamonds, with extensive production and financial data for South Africa, together with accounts of deposits and exploration in Australia, Brazil, British Guiana, India, and California. Other sections cover Colombian emeralds, garnets, Burmese jadeite, Japanese and Australian opal, pearl fisheries in Australia, India, the Persian Gulf and the United States, the Burma ruby mines at Mogok, and sapphires from Queensland. The Mogok section notes reduced ruby production and exports but increased output of sapphire and spinel, while the Australian sapphire discussion describes mining methods, production, heat-related color changes, and marketing. An additional statistical table on p. 885 summarizes mineral production in British India, including jade and diamonds.