Pyrolusite from Tuolumne County, California, USA
USA | |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 68, 323. Trask, Parker Davies, Ivan F. Wilson & F.S. Simons (1943), Manganese deposits of California – a summary report: California Division Mines Bulletin 125: 207 Day, David T. (1885), Manganese: Mineral Resources US, 1883-84: 554 |