Turquoise may be identified by mine, miner, area or district. One of the most famous turquoise mining districts is Royston located about twenty miles northwest of Tonapah NV. In this video Mike talks a bit about the history of the district and we see some examples of turquoise including a named mine in the district Royal Blue. This Royal Blue cab is 690 carats and comes from Lynn Otteson' personal collection. Photo Arland Ben.