San Rafael River: Agate & Anhydrite Rockhounding in Emery County, Utah

Quick details

Access

Public area

County

Emery County

State

Utah

Nearest road

Hatts Ranch Road

Coordinates

38.90179, -110.37488

Geology at San Rafael River

This spot sits on Alluvium and colluvium, mapped as unconsolidated alluvium and colluvium that formed within roughly the last 3 million years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.

Mapped unit

Alluvium and colluvium

Age

3 Ma to present (Quaternary)

Rock types

unconsolidated alluvium and colluvium

Elevation

4,270 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 San Rafael River

Best months: February to May. Typical highs run 97°F in midsummer and 43°F in midwinter, with winter lows near 19°F. Monsoon storms peak in July and August and can flood washes fast.

Climate normals: NOAA 1991-2020 monthlies, GOBLIN VALLEY SP station (29 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 Utah — Rockhounding overview
• Utah Geological Survey — collecting guidelines
• SITLA — surface use rules
• Community submissions reviewed against published agency rules

Found at San Rafael River

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

• AgateEncyclopedia →
• AnhydriteEncyclopedia →
• CarnotiteEncyclopedia →
• ChalcedonyEncyclopedia →
• GypsumEncyclopedia →
• JasperEncyclopedia →
• SeleniteEncyclopedia →
• Sulfur