Opal from
USA | |
| North, Jerry (2010) Displays of Nature : History, Minerals & Crystals of Utah's Bingham Canyon Copper Mine. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
(2005) Mineral Resources Data System (MRDS), US Geological Survey. | |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. Tripp, B.T. (1980), On-site Investigation, Utah Geologic and Mineral Survey |