Graphite from Gunnison County, Colorado, USA
USA | |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. Dings, McClelland G., Robinson, C.S. (1957) Geology and ore deposits of the Garfield quadrangle, Colorado. Professional Paper 289. US Geological Survey doi:10.3133/pp289 |