Bumpus Quarry: Albite & Almandine Garnet Rockhounding in Oxford County, Maine

Plan your visit

Generally open to casual rockhounding

County

Oxford County

State

Maine

Nearest road

Crooked River Causeway

Postcode

04217

Coordinates

44.31064, -70.78170

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 Bumpus Quarry

Comfortable months (45 to 90°F highs)

Best months: April to November. Typical highs run 79°F in midsummer and 28°F in midwinter, with winter lows near 8°F.

Climate normals: NOAA 1991-2020 monthlies, BETHEL 6 SSE station (1 mi away).

Geology at Bumpus Quarry

This spot sits on tonalite, mapped as tonalite that formed roughly 420 to 360 million years ago. Granitic rock like this is where pegmatite pockets tend to occur, the coarse-crystal settings that typically carry beryl, tourmaline, mica, and feldspar.

Mapped unit

tonalite

Age

420–360 Ma (Devonian)

Rock types

tonalite

Elevation

710 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.

State guidance last verified: April 1, 2026

• Maine Geological Survey
• Maine Mineral & Gem Museum
• Acadia National Park rules
• Community submissions reviewed against published agency rules