RockWoofFound alongside
Pyrite
Mohs 6–6.5. Brassy “fool’s gold,” often cubic. Mindat
11 sites
Copper
Mohs 2.5–3. Native copper is soft and turns green as it weathers. Mindat
10 sites
Magnetite
Mohs 5.5–6.5. Black and strongly magnetic. Mindat
8 sites
Quartz
Mohs 7. Six-sided points; smoky quartz is NH’s state gem. Mindat
5 sites
Gold
Mohs 2.5–3. Soft, heavy and bright yellow; it doesn’t tarnish. Mindat
3 sites
Silver
Mohs 2.5–3. Native silver tarnishes black. Mindat
2 sites
Counts are sites whose USGS record mentions the mineral or commodity. Hardness from Mindat.
By county
Carroll County (7) · Frederick County (2) · Baltimore County (1) · Montgomery County (1)
Sites
| Site | Commodity | Minerals recorded | Status | Approx. location |
|---|---|---|---|---|
| Bare Hills Copper Mine | Copper | Bornite, Carrollite, Chalcopyrite, Magnetite | Past Producer | 39.375, -76.664 |
| Mineral Hill | Copper | Bornite, Carrollite, Chalcopyrite, Magnetite, Sphalerite | Past Producer | 39.438, -76.932 |
| Patapsco | Copper | Carrollite, Chalcocite, Chalcopyrite, Covellite, Magnetite, Sphalerite | Past Producer | 39.486, -76.879 |
| Maryland Mine | Gold | Chalcopyrite, Galena, Pyrite, Pyrrhotite | Past Producer | 38.996, -77.232 |
| Monroe Prospect | — | — | Prospect | 39.426, -76.948 |
| Patapsco Mines | — | — | Past Producer | 39.489, -76.877 |
| New London Mine | — | — | Past Producer | 39.419, -77.260 |
| Beasman Prospect | — | — | Prospect | 39.433, -76.933 |
| Mineral Hill Mine | — | — | Past Producer | 39.438, -76.930 |
| Springfield Mine | — | — | Past Producer | 39.381, -76.975 |
| Liberty Mine | — | — | Past Producer | 39.513, -77.254 |
Back to Rockhounding in Maryland.
How we built this page: we counted named sites in the USGS Mineral Resources Data System (MRDS) for this area, left out sand, gravel, crushed stone, clay pits and unnamed sites, grouped them by Census county, and linked every site to its USGS record. We did not visit these sites, and MRDS does not tell you who owns the land or whether collecting is allowed.
Source: USGS Mineral Resources Data System (MRDS). USGS ceased systematic updates to MRDS around 2011, so status and details may be out of date. Each site links to its USGS record.
Updated