Girty: Hematite & Magnetite Rockhounding in Armstrong County, Pennsylvania

Plan your visit

Generally open to casual rockhounding

County

Armstrong County

State

Pennsylvania

Nearest road

PA 56;PA 156

Coordinates

40.63535, -79.40725

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.

Best time to visit Girty

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 84°F in midsummer and 35°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, FORD CITY 4 S DAM station (8 mi away).

Geology at Girty

This spot sits on Allegheny Formation, mapped as sandstone that formed roughly 325 to 300 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Mapped unit

Allegheny Formation

Age

325–300 Ma (Pennsylvanian)

Rock types

sandstone

Elevation

1,000 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.

• Pennsylvania Geological Survey
• DCNR state park and state forest rules
• Allegheny National Forest
• Community submissions reviewed against published agency rules