Spencer Opal Mine: Fire Opal Rockhounding in Clark County, Idaho

Updated June 2026

Spencer Opal Mine is a mapped rockhounding spot in Clark County, Idaho. Reported finds include fire opal. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Paid / fee dig
County: Clark County
State: Idaho
Nearest road: Old Highway 91
Postcode: 83446
Coordinates: 44.36143, -112.18646

Geology at Spencer Opal Mine

This spot sits on Sedimentary rocks (Paleocene and Cretaceous), mapped as conglomerate and sandstone that formed roughly 145 to 56 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Mapped unit: Sedimentary rocks (Paleocene and Cretaceous)
Age: 145–56 Ma (Cretaceous to Paleocene)
Rock types: conglomerate and sandstone
Elevation: 5,900 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.

Best time to visit Spencer Opal Mine

Best months: April to October. Typical highs run 85°F in midsummer and 28°F in midwinter, with winter lows near 13°F.

Climate normals: NOAA 1991-2020 monthlies, DUBOIS EXP STN station (8 mi away), adjusted for elevation.

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.

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

Idaho Panhandle National Forests — Emerald Creek
Idaho Geological Survey
Spencer Opal Mines (fee-dig operator)
Community submissions reviewed against published agency rules

Found at Spencer Opal Mine

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

Fire Opal Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Spencer Opal Mine.

Across the state line from Spencer Opal Mine

Spencer Opal Mine is close enough to the Idaho border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Spencer Opal Mine FAQ

Where is Spencer Opal Mine?+

Spencer Opal Mine is in Clark County, Idaho, at 44.36143, -112.18646. Nearest road: Old Highway 91.

What rocks and minerals can you find at Spencer Opal Mine?+

Spencer Opal Mine is reported to produce Fire Opal.

Is collecting allowed at Spencer Opal Mine?+

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. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Spencer Opal Mine?+

Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.

When is the best time to visit Spencer Opal Mine?+

The most comfortable months at Spencer Opal Mine are April to October.

How do I get to Spencer Opal Mine?+

Open the directions link to navigate to 44.36143, -112.18646 in Google Maps. The nearest road is Old Highway 91.

More rockhounding in Idaho

See all 115 Idaho spots →

Open Spencer Opal Mine on the map

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