Opal-AN from Pennsylvania, USA
USA | |
| The Mineralogy of Pennsylvania 1966-1975 Robert C. Smith II pg. 53 |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 229 |
Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 229 | |
| Mineralogy of Pennsylvania, S. G. Gordon - 1922, p. 226. |
Gordon, 1922. The Mineralogy of Pennsylvania |
Dyer Quarry, Gibraltar, Birdsboro, Berks County, Pennsylvania, USA