Tres Hermanas Mts: Dumortierite & Hydrozincite Rockhounding in Luna County, New Mexico

Updated June 2026

Tres Hermanas Mts is a mapped rockhounding spot in Luna County, New Mexico. Reported finds include dumortierite, hydrozincite, pyrolusite, quartz, smithsonite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Luna County
State: New Mexico
Nearest road: cdt
Coordinates: 31.93075, -107.72552

Geology at Tres Hermanas Mts

This spot sits on Hueco Formation or Group, mapped as limestone and shale that formed roughly 300 to 285 million years ago. Carbonate rock like this dissolves and weathers readily, so fresh road cuts, quarries, and creek exposures are typically the most productive ground.

Mapped unit: Hueco Formation or Group
Age: 300–285 Ma (Cisuralian)
Rock types: limestone and shale
Elevation: 4,650 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 Tres Hermanas Mts

Best months: September to May. Typical highs run 94°F in midsummer and 57°F in midwinter, with winter lows near 29°F. Summer heat here is intense, so carry more water than you think you need and work the early morning.

Climate normals: NOAA 1991-2020 monthlies, COLUMBUS station (9 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 Tres Hermanas Mts

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 Tres Hermanas Mts.

Across the state line from Tres Hermanas Mts

Tres Hermanas Mts 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.

General AreaEl Paso County, Texas · 71 mi awayGarnet, Mica, Pink Serpentine

Tres Hermanas Mts FAQ

Where is Tres Hermanas Mts?+

Tres Hermanas Mts is in Luna County, New Mexico, at 31.93075, -107.72552. Nearest road: cdt.

What rocks and minerals can you find at Tres Hermanas Mts?+

Tres Hermanas Mts is reported to produce Dumortierite, Hydrozincite, Pyrolusite, Quartz, Smithsonite, Willemite.

Is collecting allowed at Tres Hermanas Mts?+

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 Tres Hermanas Mts?+

A rock hammer, a small pry bar, gloves, and safety glasses cover most crystal ground. A screen helps in loose pocket soil, and newspaper protects points on the way out.

When is the best time to visit Tres Hermanas Mts?+

The most comfortable months at Tres Hermanas Mts are September to May. Summer heat here is intense, so carry more water than you think you need and work the early morning.

How do I get to Tres Hermanas Mts?+

Open the directions link to navigate to 31.93075, -107.72552 in Google Maps. The nearest road is cdt.

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