Aurora Mine (permission required): Serpentine Rockhounding in San Benito County, California

Quick details

Access

Permission required

County

San Benito County

State

California

Nearest road

Mexican Lake Road

Coordinates

36.39486, -120.67414

Geology at Aurora Mine (permission required)

This spot sits on Ultramafic rocks, chiefly Mesozoic, unit 3 (Coast Ranges and Western Klamath Mountains), mapped as serpentinite that formed roughly 175 to 145 million years ago. Metamorphic rock like this weathers into resistant float, and minerals that survive transport typically concentrate in nearby drainages.

Mapped unit

Ultramafic rocks, chiefly Mesozoic, unit 3 (Coast Ranges and Western Klamath Mountains)

Age

175–145 Ma (Middle Jurassic to Late Jurassic)

Rock types

serpentinite

Elevation

3,840 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 Aurora Mine (permission required)

Best months: September to July. Typical highs run 90°F in midsummer and 54°F in midwinter, with winter lows near 25°F.

Climate normals: NOAA 1991-2020 monthlies, PRIEST VALLEY station (14 mi away), adjusted for elevation.

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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

Found at Aurora Mine (permission required)

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

• SerpentineEncyclopedia →