- GeoRef, Copyright 2006, American Geological Institute. Abstract, Copyright, Society of Economic Geologists. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
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.