gems, turquoise, Iran, Persia, Nishapur

The article, based principally on reports by Nicolas, Houtum Schindler, and Tietze, gives a detailed account of the celebrated turquoise mines of Nishapur, described as the most important known deposit of the gem. The mines lie in the Bar-i-Máden district, northwest of Nishapur, where the inhabitants were largely dependent upon turquoise mining. Geologically, the turquoise occurs chiefly as numerous thin veinlets, generally 2–4 mm and at most 6 mm thick, cutting a breccia of porphyritic trachyte cemented by iron oxide; turquoise also occurs as broken fragments and in surface alluvium. Tietze suggests that apatite in the trachyte may have supplied the phosphate necessary for turquoise formation. Two types of workings are distinguished: underground mines, of which 266 shafts were active in 1876 and some reached depths of 100–160 feet, and the superficial alluvial “Khagi,” which were then yielding some of the finest stones. Mining was poorly organized and dangerous, with frequent collapses; picks, bars, and gunpowder were used, although blasting tended to shatter the turquoise. The article provides unusually detailed information on quality and valuation: turquoise was divided into Engouchtèri, Barkhanèh, and Arabi grades, with the finest stones judged particularly by a deep sky-blue color and the difficult-to-define quality called “zât,” compared with the “water” of a diamond or “orient” of a pearl. Some newly mined turquoise retained a fine color only while moist, becoming greenish, gray, or eventually almost white upon drying; such unstable material had damaged the reputation of turquoise in European markets. The account also describes cutting and polishing techniques, local and international marketing through Mashhad and Moscow, substantial increases in price between mine and European market, and changing systems of taxation, leasing, and state control. It is thus an exceptionally detailed nineteenth-century account of the geology, mining, grading, treatment, cutting, commerce, and economics of Persian turquoise.