Chalcedony from St Peters Dome, Cheyenne Mining District (St. Peters Dome Mining District), El Paso County, Colorado, USA
USA | |
| Pearl, R.M. (1958) Colorado Gem Trails & Mineral Guide. Sage Books, Chicago, Illinois. |
Landes, K.K. (1935) Colorado Pegmatites. American Mineralogist, 20(5), 319-333. |