Minerals and Rocks

The state of California hosts a rich variety of minerals and rocks. The California Geological Survey provides objective geologic expertise and information about California’s diverse non-fuel mineral resources, producing maps, reports, and other data products to assist governmental agencies, mining companies, consultants, and the public in recognizing, developing, and protecting important mineral resources.

We'll be adding more to this page in the future, so check back often. In the meantime, please feel free to explore the topics below:

Ohama Mine - Grass Valley, CA

Historic Gold Mines - In recognition of the California Gold Discovery to Statehood Sesquicentennial (1998-2000) CGS produced the "Map of Californi​a Historic Gold Mines" as a poster at the scale of 1:1,500,000. The map shows the location of 13,500 historic California gold mines. Click on image for larger view.

serpentine specimen

Serpentine - California State Rock - Serpentine is the metamorphosed remains of magnesium-rich igneous rocks, most commonly peridotite, from the earth's mantle. Serpentine rock is apple-green to black and is often mottled with light and dark colored areas. Its surfaces often have a shiny or wax-like appearance and a slightly soapy feel. Serpentine is usually fine-grained and compact but may be granular, platy, or fibrous in appearance. Serpentine may contain asbestos. Click on image for larger view.

gold specimen

Gold - California State Mineral - State legislation signed on April 23,1965 designated native gold as California's official state mineral. At the signing ceremony Governor Edmund G. Brown Sr. said, "Selection of gold as our state mineral is acknowledgement of the intimate part it has played in the history of our people and of the fact that mining is a major California economic activity." Click on image for larger view.

benitoite specimen

Benitoite - California State Gem - On October 1, 1985 benitoite was designated as the official state gem. Named in 1907 after the river, county, and nearby mountain range where it was found. "Benito" is a spanish form of benedictus, meaning blessed. Crystals can occur in a rich blue color as striking and flawless as the finest sapphires. Click on image for larger view.