Greenfire Opal Mine: Opal & Black Opal Rockhounding in Humboldt County, Nevada

Plan your visit

Permission required before collecting

County

Humboldt County

State

Nevada

Nearest road

Sagebrush Creek Road

Coordinates

41.81482, -119.00795

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

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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 Greenfire Opal Mine

Comfortable months (45 to 90°F highs)

Best months: February to June. Typical highs run 92°F in midsummer and 41°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, DENIO station (23 mi away), adjusted for elevation.

Geology at Greenfire Opal Mine

This spot sits on Younger tuffaceous sedimentary rocks, mapped as sedimentary and volcanic 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

Younger tuffaceous sedimentary rocks

Age

23–3 Ma (Miocene to Pliocene)

Rock types

sedimentary and volcanic

Elevation

4,900 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

• BLM Nevada, Recreation
• Nevada Bureau of Mines and Geology
• Royal Peacock Opal Mine (fee-dig operator)
• Community submissions reviewed against published agency rules