RockWoofFound alongside
Quartz
Mohs 7. Six-sided points; smoky quartz is NH’s state gem. Mindat
14 sites
Gold
Mohs 2.5–3. Soft, heavy and bright yellow; it doesn’t tarnish. Mindat
5 sites
Pyrite
Mohs 6–6.5. Brassy “fool’s gold,” often cubic. Mindat
5 sites
Copper
Mohs 2.5–3. Native copper is soft and turns green as it weathers. Mindat
5 sites
Magnetite
Mohs 5.5–6.5. Black and strongly magnetic. Mindat
4 sites
Silver
Mohs 2.5–3. Native silver tarnishes black. Mindat
1 site
Counts are sites whose USGS record mentions the mineral or commodity. Hardness from Mindat.
By county
Montgomery County (4) · Carroll County (4) · Frederick County (2) · Howard County (2) · Baltimore County (1) · Garrett County (1)
Sites
| Site | Commodity | Minerals recorded | Status | Approx. location |
|---|---|---|---|---|
| Bethesda Mine | Gold | Gold, Quartz | Past Producer | 38.997, -77.127 |
| Sawyer Mine | Gold | Quartz | Past Producer | 38.988, -77.204 |
| Irma Mine | Gold | Quartz | Past Producer | 38.986, -77.201 |
| Lynch Mine | Gold | Quartz | Past Producer | 38.987, -77.191 |
| Weaver Stone Company Quarry | Quartz | — | Past Producer | 39.541, -76.731 |
| Green Valley Road Quarry | Quartz | — | Past Producer | 39.534, -77.204 |
| Marriottsville Quarry | Quartz | — | Past Producer | 39.365, -76.899 |
| Patapsco Quarry | Quartz | — | Past Producer | 39.344, -76.902 |
| Louis A Morgart Clay Deposit | — | — | Prospect | 39.622, -79.187 |
| 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 |
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 USGS ceased systematic updates to MRDS around 2011, so status and details may be out of date.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