Granite Mountains: Chalcedony Rockhounding in Natrona County, Wyoming

Updated June 2026

Granite Mountains is a mapped rockhounding spot in Natrona County, Wyoming. Reported finds include chalcedony. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Natrona County
State: Wyoming
Coordinates: 42.47174, -107.17959

Geology at Granite Mountains

This spot sits on ground mapped as Alluvial deposits that formed within roughly the last 12,000 years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.

Mapped unit: Alluvial deposits
Age: < 1 Ma (Holocene)
Elevation: 5,920 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 Granite Mountains

Best months: March to November. Typical highs run 88°F in midsummer and 33°F in midwinter, with winter lows near 16°F.

Climate normals: NOAA 1991-2020 monthlies, MUDDY GAP station (15 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 Wyoming
Wyoming State Geological Survey
Fossil Butte National Monument
Community submissions reviewed against published agency rules

Found at Granite Mountains

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

Chalcedony Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Granite Mountains.

Granite Mountains FAQ

Where is Granite Mountains?+

Granite Mountains is in Natrona County, Wyoming, at 42.47174, -107.17959.

What rocks and minerals can you find at Granite Mountains?+

Granite Mountains is reported to produce Chalcedony.

Is collecting allowed at Granite Mountains?+

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

What tools should I bring to Granite Mountains?+

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 Granite Mountains?+

The most comfortable months at Granite Mountains are March to November.

How do I get to Granite Mountains?+

Open the directions link to navigate to 42.47174, -107.17959 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Wyoming

See all 82 Wyoming spots →

Open Granite Mountains on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.