Crane Mountain: Agate & Jasper Rockhounding in Lake County, Oregon

Quick details

Access

Public area

County

Lake County

State

Oregon

Coordinates

42.06875, -120.29014

Geology at Crane Mountain

This spot sits on volcanic rocks, mapped as siltstone, dark gray, green brown, red brown, claystone, tuff breccia, ash-flow tuff, light; lithology: dacite, rhyolite, and sandstone that formed roughly 34 to 5 million years ago. Volcanic ground like this is where agate, jasper, and other chalcedony typically form, filling old gas pockets and fracture seams in the flow rock.

Mapped unit

volcanic rocks

Age

34–5 Ma (Oligocene to Miocene)

Rock types

siltstone, dark gray, green brown, red brown, claystone, tuff breccia, ash-flow tuff, light; lithology: dacite, rhyolite, and sandstone

Elevation

5,200 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 Crane Mountain

Best months: March to November. Typical highs run 85°F in midsummer and 38°F in midwinter, with winter lows near 21°F.

Climate normals: NOAA 1991-2020 monthlies, LAKEVIEW 2 NNW station (13 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.

State guidance last verified: April 1, 2026

• BLM Oregon/Washington — Rockhounding & mineral material
• Oregon Department of Geology and Mineral Industries (DOGAMI)
• Oregon Parks and Recreation Department — beach collecting rules
• Community submissions reviewed against published agency rules

Found at Crane Mountain

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

• AgateEncyclopedia →
• JasperEncyclopedia →
• ThundereggsEncyclopedia →