Opal from Great Hill cobalt mines, Cobalt, East Hampton (Chatham), Middlesex County, Connecticut, USA
USA | |
| [Opal-A var. Opal-AN] Januzzi, Ron E., Seaman, David M. (1976) Mineral Localities of Connecticut and Southeastern New York State and Pegmatite Minerals of the World. The Mineralogical Press, Danbury, Connecticut, USA. |