Tripp Mine: Beryl & Aquamarine Rockhounding in Cheshire County, New Hampshire

Plan your visit

Pay-to-dig site

County

Cheshire County

State

New Hampshire

Nearest road

Gilsum Mine Road

Coordinates

43.08188, -72.27941

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

Land & collecting status

Pay-to-dig site

This is a fee-dig location. Hours, prices, and what you can keep vary by operator. Call ahead before driving out.

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 Tripp Mine

Comfortable months (45 to 90°F highs)

Best months: April to October. Typical highs run 78°F in midsummer and 28°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, WALPOLE 2S NEPP station (8 mi away), adjusted for elevation.

Geology at Tripp Mine

This spot sits on Lower part of Rangeley Formation, mapped as metasedimentary that formed roughly 445 to 435 million years ago. Metamorphic belts like this often host pegmatite dikes, the coarse-crystal bodies that typically carry beryl, tourmaline, and sheet mica.

Mapped unit

Lower part of Rangeley Formation

Age

445–435 Ma (Llandovery)

Rock types

metasedimentary

Elevation

1,330 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.

• White Mountain National Forest
• New Hampshire Geological Survey
• New Hampshire State Parks rules
• Community submissions reviewed against published agency rules