Mimbres Mountains: Agate & Chalcedony Rockhounding in Sierra County, New Mexico

Updated June 2026

Mimbres Mountains is a mapped rockhounding spot in Sierra County, New Mexico. Reported finds include agate, chalcedony, chert, chrysocolla, jasper, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Sierra County
State: New Mexico
Nearest road: Trail #135
Coordinates: 32.84410, -107.73604

Geology at Mimbres Mountains

This spot sits on Lower middle Tertiary andesitic to dacitic lavas and pyroclastic flow breccias, mapped as andesite and latite that formed roughly 48 to 28 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: Lower middle Tertiary andesitic to dacitic lavas and pyroclastic flow breccias
Age: 48–28 Ma (Middle Eocene to Early Oligocene)
Rock types: andesite and latite
Elevation: 7,080 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 Mimbres Mountains

Conditions here are workable year-round, with typical highs from 48°F in winter to 85°F in summer. At about 7,080 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, HILLSBORO station (11 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

Rockhound State Park — Collection rules
BLM New Mexico
New Mexico Bureau of Geology and Mineral Resources
Community submissions reviewed against published agency rules

Found at Mimbres Mountains

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

Nearby rockhounding spots

Other rockhounding spots within driving distance of Mimbres Mountains.

Across the state line from Mimbres Mountains

Mimbres Mountains is close enough to the New Mexico border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Both sides of Mule Creek RoadGreenlee County, Arizona · 79 mi awayChalcedony Geode

Mimbres Mountains FAQ

Where is Mimbres Mountains?+

Mimbres Mountains is in Sierra County, New Mexico, at 32.84410, -107.73604. Nearest road: Trail #135.

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

Mimbres Mountains is reported to produce Agate, Chalcedony, Chert, Chrysocolla, Jasper, Fluorite.

Is collecting allowed at Mimbres 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 Mimbres 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 Mimbres Mountains?+

Mimbres Mountains is workable year-round. At about 7,080 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

How do I get to Mimbres Mountains?+

Open the directions link to navigate to 32.84410, -107.73604 in Google Maps. The nearest road is Trail #135.

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