Quartz Mountain Pass: Agate & Chalcedony Rockhounding in Lake County, Oregon

Quick details

Access

Public area

County

Lake County

State

Oregon

Nearest road

Forest Road 3660

Coordinates

42.32338, -120.81192

Geology at Quartz Mountain Pass

This spot sits on Early Winema Volcanic Field, mapped as rhyodacite flows that formed roughly 23 to 3 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

Early Winema Volcanic Field

Age

23–3 Ma (Miocene to Pliocene)

Rock types

rhyodacite flows

Elevation

5,450 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 Quartz Mountain Pass

Best months: March to November. Typical highs run 83°F in midsummer and 39°F in midwinter, with winter lows near 18°F.

Climate normals: NOAA 1991-2020 monthlies, BLY 4 SE station (14 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 Quartz Mountain Pass

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

• AgateEncyclopedia →
• ChalcedonyEncyclopedia →
• JasperEncyclopedia →