Abstract

Turquoise of gem quality occurs at Courtland, southeastern Cochise County, Arizona, in Upper Cambrian Bolsa quartzite and in granite of post-Cretaceous age. The turquoise has been deposited from solution in fracture zones caused by normal faulting prior to a period of thrust faulting. Its origin is genetically related to the granite. Limonite, kaolin, and sericite are associated minerals. Turquoise is found through a vertical range of 180 feet and is mined through shallow shafts, open cuts, and adits. The rough stone is sold to dealers and Indian traders.

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