Del Norte Thunder Egg Beds: Plume Agate & Moss Agate Rockhounding in Saguache County, Colorado

Plan your visit

Generally open to casual rockhounding

County

Saguache County

State

Colorado

Coordinates

37.76147, -106.44808

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

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.

Access note: The site is about 7.5 miles northwest of Del Norte along Old Woman Creek on federal public land, reached by rough dirt road suited to high-clearance vehicles. Collecting on the National Forest portion requires a free-use permit from the Divide Ranger District and limits ground disturbance, so confirm the parcel and rules before digging.

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.

Best time to visit Del Norte Thunder Egg Beds

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 77°F in midsummer and 31°F in midwinter, with winter lows near 4°F. At about 8,830 ft, snow can block access from late fall well into spring, so check conditions outside of summer.

Climate normals: NOAA 1991-2020 monthlies, DEL NORTE 3ENE station (9 mi away), adjusted for elevation.

Geology at Del Norte Thunder Egg Beds

This spot sits on Pre-ash-flow andesitic lavas, breccias, tuffs, and conglomerates, mapped as andesite that formed roughly 38 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

Pre-ash-flow andesitic lavas, breccias, tuffs, and conglomerates

Age

38–28 Ma (Late Eocene to Early Oligocene)

Rock types

andesite

Elevation

8,830 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.

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.

• BLM Colorado rockhounding rules
• Colorado Geological Survey
• Pike and San Isabel National Forests
• Community submissions reviewed against published agency rules