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Fort Sumner: Quartz & Pecos Diamonds Rockhounding in De Baca County, New Mexico

Q: Where is Fort Sumner?

Fort Sumner is in De Baca County, New Mexico, at 34.45906, -104.23960. Nearest road: South 9th Street.

Q: What rocks and minerals can you find at Fort Sumner?

Fort Sumner is reported to produce Quartz, Pecos Diamonds.

Q: Is collecting allowed at Fort Sumner?

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.

Q: What tools should I bring to Fort Sumner?

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.

Q: When is the best time to visit Fort Sumner?

The most comfortable months at Fort Sumner are August to May.

Q: How do I get to Fort Sumner?

Open the directions link to navigate to 34.45906, -104.23960 in Google Maps. The nearest road is South 9th Street.

Updated June 2026

Fort Sumner represents the Pecos diamond belt, where the collectible material is doubly terminated authigenic quartz rather than true diamond. New Mexico Bureau of Geology publications tie these quartz and occasional dolomite crystals to Seven Rivers Formation and related Artesia Group outcrops, and Mindat records the De Baca County occurrence as a named Pecos diamond locality. Reported finds include quartz, pecos diamonds. Below: coordinates, access notes, nearby spots, and trip-planning links.

Fort Sumner photos

Public image records connected to this spot or its reported material.

2 photos

Quick details

Access: Public area
County: De Baca County
State: New Mexico
Nearest road: South 9th Street
Postcode: 88119
Coordinates: 34.45906, -104.23960

Geology at Fort Sumner

This spot sits on Alluvium, mapped as unconsolidated alluvium that formed within roughly the last 129,000 years. Loose deposits like these are float-collecting ground: erosion keeps moving durable rocks and minerals into gravel bars, cutbanks, and washes.

Mapped unit: Alluvium
Age: < 1 Ma (Late Pleistocene to Holocene)
Rock types: unconsolidated alluvium
Elevation: 4,000 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 Fort Sumner

Best months: August to May. Typical highs run 92°F in midsummer and 55°F in midwinter, with winter lows near 25°F.

Climate normals: NOAA 1991-2020 monthlies, FT SUMNER station (1 mi away).

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 Fort Sumner

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 Fort Sumner.

Fort Sumner FAQ

Where is Fort Sumner?+

Fort Sumner is in De Baca County, New Mexico, at 34.45906, -104.23960. Nearest road: South 9th Street.

What rocks and minerals can you find at Fort Sumner?+

Fort Sumner is reported to produce Quartz, Pecos Diamonds.

Is collecting allowed at Fort Sumner?+

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 Fort Sumner?+

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 Fort Sumner?+

The most comfortable months at Fort Sumner are August to May.

How do I get to Fort Sumner?+

Open the directions link to navigate to 34.45906, -104.23960 in Google Maps. The nearest road is South 9th Street.

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