Mine Dumps (San Diego Co.): Aquamarine & Beryl Rockhounding in San Diego County, California

Plan your visit

Generally open to casual rockhounding

County

San Diego County

State

California

Nearest road

Highway 76

Coordinates

33.23547, -116.75911

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.

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 Mine Dumps (San Diego Co.)

Comfortable months (45 to 90°F highs)

Best months: September to June. Typical highs run 92°F in midsummer and 60°F in midwinter, with winter lows near 31°F.

Climate normals: NOAA 1991-2020 monthlies, HENSHAW DAM station (0 mi away).

Geology at Mine Dumps (San Diego Co.)

This spot sits on pre-Cenozoic granitic and metamorphic rocks undivided, mapped as plutonic and gneiss that formed roughly 2500 to 66 million years ago. Granitic ground like this typically carries quartz veins and pockets, and weathered crystals tend to collect in the soils and drainages below.

Mapped unit

pre-Cenozoic granitic and metamorphic rocks undivided

Age

2500–66 Ma (Paleoproterozoic to Late Cretaceous)

Rock types

plutonic and gneiss

Elevation

2,780 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.

State guidance last verified: April 1, 2026

• BLM California, Recreational mineral collecting
• California Geological Survey
• CDFW, Suction Dredge Mining Permit Program
• Community submissions reviewed against published agency rules