|
USA | |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Betts, John (n.d.) John Betts website listing. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Dario Cericola collection |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Jat Thompson Collection |
| Jat Thompson Collection |
| Ref: Minerals of the Washington, D.C Area. |
| Jat Thompson Collection |
| Jat Thompson Collection |
| Rocks & Min.:11:43. |
| [var. SphΓ€rosiderite] Ostrander, C. W. & W. E. Price (1940) Minerals of Maryland: Natural History Society of Maryland , 92 p. |
| Maryland Geologic Survey, Vol. VIII (1898): 164. Dana 6:1070 Rocks & Min.:10:110 |
| Maryland Geological Survey, Volume 8, Baltimore, John Hopkins Press, 1909, page 154. |
| |
| Bulletin of the United States National Museum, Volumes 42 By United States National Museum |
| Mines of the Washington D.C Area |
| Jat Thompson Collection |
| Ostrander, C. W. & W. E. Price (1940) Minerals of Maryland: Natural History Society of Maryland , 92 p. |
| Mines of the Washington D.C Area |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| (2005) Mineral Resources Data System (MRDS), US Geological Survey. |
| Jat Thompson Collection |
| Ref: Minerals of the Washington, D.C Area. |
| Bernstein, Lawrence (1976) Minerals of Washington D.C. and vicinity: U.S. Geological Survey: Open File Report 76-849, 183 p. |
| Bernstein, Lawrence (1976) Minerals of Washington D.C. and vicinity: U.S. Geological Survey: Open File Report 76-849, 183 p. |
| William S. Cordua |
Frostburg, Allegany County, Maryland, USA