Overview
California's geology gave the country the Gold Rush and a remarkable mineral variety, from the gem tourmalines of San Diego County to jade on the Big Sur coast and the state's own unique blue gem, benitoite. Its rocks tell the story of a colliding plate margin.
This guide covers common and iconic California minerals — how to recognize them by color, luster, and form. Photograph your specimen from a couple of angles and use the app to help confirm what you have found.
Key Species to Know
Gold
Gold
California's state mineral and the spark of the 1849 Gold Rush — soft, heavy, buttery-yellow metal found as flakes and nuggets in Sierra streams and quartz veins.
Benitoite
Benitoite
California's state gem — a rare, brilliant sapphire-blue mineral that fluoresces bright blue under UV light. Found in gem quality essentially only in San Benito County.
Jade (Nephrite)
Nephrite
A tough, waxy green stone prized for carving, famously collected as beach and cove cobbles along the Big Sur coast at Jade Cove.
Tourmaline
Tourmaline
A gem mineral forming long, striated crystals in pink, green, and "watermelon" color zones, from the world-famous pegmatite mines of San Diego County.
Serpentine
Serpentinite
California's state rock — a slick, greenish, often mottled metamorphic rock, sometimes soapy to the touch, that marks ancient ocean-floor and fault zones.
Quartz
Quartz
The common glassy, hard mineral that hosts much of California's gold. Clear to white, with six-sided crystals and curved, shell-like fractures.
Seasonal Guide
- Coastal jade hunting is best at low tide, especially after winter storms churn up fresh cobbles.
- Gold panning is a Sierra tradition — check current rules, claims, and access before working any stream.
- Carry a UV light to spot the striking blue fluorescence of benitoite.
Safety Reminder
This is an identification guide only. Respect mining claims and private property, follow the rules on public land (collecting is prohibited in state and national parks), and stay off unstable sea cliffs and out of abandoned mines. Watch the tides on the coast.
Identify it instantly
Found something and not sure what it is? Point your camera with Spotter and get a species identification in seconds — with detailed reference info and species notes.