Cyrtolite from Gunnison County, Colorado, USA
USA | |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
Meeves, H., et al (1966), Reconnaissance of beryllium-bearing pegmatite deposits in six western states, US Bur. Mines Info. Circ. 8298: 26 (Table A-1). |