Piney Mountain: Piedmontite Rockhounding in Adams County, Pennsylvania

Quick details

Access

Public area

County

Adams County

State

Pennsylvania

Nearest road

Pine Grove Road

Coordinates

39.96129, -77.39936

Geology at Piney Mountain

This spot sits on Montalto Member of Harpers Formation, mapped as quartzite that formed roughly 540 to 485 million years ago. Metamorphic rock like this weathers into resistant float, and minerals that survive transport typically concentrate in nearby drainages.

Mapped unit

Montalto Member of Harpers Formation

Age

540–485 Ma (Cambrian)

Rock types

quartzite

Elevation

1,560 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.

Best time to visit Piney Mountain

Best months: March to November. Typical highs run 82°F in midsummer and 34°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, CASHTOWN 1S station (6 mi away), adjusted for elevation.

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.

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.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Piney Mountain

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

• Piedmontite