Granite: Quartz & Garnet Rockhounding in Baltimore County, Maryland

Plan your visit

Generally open to casual rockhounding

County

Baltimore County

State

Maryland

Nearest road

Quarry Trail

Postcode

21163

Coordinates

39.34544, -76.86371

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Geology at Granite

This spot sits on Baltimore Gneiss, mapped as gneiss that formed roughly 4600 to 540 million years ago. Metamorphic terrain like this typically carries quartz veins and sweats, and weathered crystals tend to end up in the soils and streams below.

Mapped unit

Baltimore Gneiss

Age

4600–540 Ma (Precambrian)

Rock types

gneiss

Elevation

470 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

• Maryland Geological Survey
• Maryland DNR state park rules
• Calvert Marine Museum fossil guidance
• Community submissions reviewed against published agency rules