Opal from Putnam County, New York, USA
USA | |
| [Opal-A var. Opal-AN] Rocks & Min.:8:61-65. |
| [Opal-A var. Opal-AN] Manchester, James G. (1931) The Minerals of New York City and its Environs. Bulletin of the New York Mineralogical Club Vol. 3 (1) New York Mineralogical Club |
| [Opal-A var. Opal-AN] Januzzi, 1976. Mineral Localities of CT and Southeastern NY State, p223-224 |
Jensen (1978) Minerals of New York State, 42-43 (Januzzi, 1966, 1989) (Trainer, 1938). |