Helvine from Colorado, USA
USA | |
| www.coloradomineralsociety.org (2016) http://www.coloradomineralsociety.org/newsletters/March2014.pdf |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| 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). |
| Min News 20:9 pp1,3,10,11 |
| Burbank, W. S. (1933): The manganese minerals of the Sunnyside veins, Eureka Gulch, Colorado. American Mineralogist 18, 513-527. Rocks & Min.: 63: 366-384. |
In Collection of Martin Slama |
Sunnyside Mine group, Bonita Peak, Gladstone, Eureka Mining District, San Juan County, Colorado, USA