Brookdale Mine: Quartz & Pyromorphite Rockhounding in Chester County, Pennsylvania

Plan your visit

Generally open to casual rockhounding

County

Chester County

State

Pennsylvania

Nearest road

Anna Louise Lane

Postcode

19460

Coordinates

40.10111, -75.52083

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.

Access note: Old mine workings in Chester County; surface dumps and tailings are the practical collecting areas. Much surrounding land is private or posted, so confirm access and permission before collecting and stay clear of any open shafts or unstable ground.

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 Brookdale Mine

Comfortable months (45 to 90°F highs)

Best months: March to December. Typical highs run 87°F in midsummer and 41°F in midwinter, with winter lows near 22°F.

Climate normals: NOAA 1991-2020 monthlies, PHOENIXVILLE 1 E station (2 mi away).

Geology at Brookdale Mine

This spot sits on Felsic and intermediate gneiss, mapped as muscovite 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

Felsic and intermediate gneiss

Age

4600–540 Ma (Precambrian)

Rock types

muscovite gneiss

Elevation

240 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