California is an extraordinary state for rockhounding. Geological forces have created one of the widest varieties of rocks and minerals found in any state. The state, also known as the ‘Golden State,’ is home to amazing national parks (Yosemite, Lassen, Death Valley, & Joshua Tree) and national monuments (Devils Postpile & Lava Caves) as well as thousands of historic gold mines. Aside from gold, California long has been famous for fantastic tourmaline deposits as well as obsidian. In addition, California has numerous minerals, gemstones, and fossils as well as oil and gas deposits. The Rancho La Brea Tar Pits is one of the world's most famous Ice Age fossil sites. The state also is the site of the second largest meteorite found in the United States.
State Rocks, Gemstones, Minerals, Fossils, & Dinosaurs
Rockhounding Tip: Knowing state rocks, gemstones, minerals, fossils, and dinosaurs often can be very useful information for rockhounders. Ordinarily, states with significant mineral deposits, valuable gemstones, fossils, or unusual or significant rock occurrences will designate an official state mineral, rock/stone, gemstone, fossil, or dinosaur to promote interest in the state’s natural resources, history, tourism, etc. Accordingly, such state symbols often are a valuable clue as to potential worthwhile rockhounding opportunities.
State Rock: Serpentine (1965)
California was the first state to designate an official state rock. In 1965, California designated Serpentine as the official state rock. Serpentine is apple-green to black in color and is often mottled with light and dark colored areas. It has a shiny or wax-like appearance and slightly soapy feel. Serpentine usually is fine-grained and compact but may be granular, platy, or fibrous. It occurs in central and northern California – in the Coast Ranges, Klamath Mountains, and Sierra Nevada foothills. Serpentine primarily is composed of one or more of the three magnesium silicate minerals: lizardite, chrysotile, and antigorite. Serpentine is metamorphic and/or magnesium-rich igneous rock, most commonly peridotite, from the earth’s mantle. In 2010, a few California legislators attempted to pass legislation to remove serpentine as the official state rock because the rock (which occurs in 42 of California’s 58 counties) contains very small amounts of naturally occurring asbestos – much like many other natural resources. The bill (SB 624) passed the state senate, but then failed to pass the state house.
State Gemstone: Benitoite (1985)
California designated benitoite as the official state gemstone in 1985. Sometimes called the 'blue diamond,' benitoite was named in 1907 after the river (San Benito River), county, and nearby mountain range where it was found. "Benito" is a spanish form of benedictus, meaning blessed. The barium-titanium silicate gem is extremely rare and ranges in color from a light transparent blue to dark, vivid sapphire blue, and occasionally it is found in a violet shade. Gem quality benitoite is found found only in San Benito County, California. The crystals form as well-defined triangles as seen in this specimen.
State Mineral: Native Gold (1965)
California designated native gold as the state mineral in 1965. The accidental discovery of gold in 1848 at Sutter’s Mill in Coloma started a bonanza that brought California fame and gave it the title of the “Golden State.” The Gold Rush of 1849 (which was not the first gold rush in America) and the subsequent influx of settlers led to California becoming the 31st state in 1850. In the four years following the discovery of gold by James Marshall in January of 1848, California's population swelled from 14,000 to 250,000 people. Miners came from all over the world and extracted 28,280,711 fine ounces of gold from 1850 – 1859 that would be worth over ten billion dollars today. There are thousands of historic gold mines throughout California. Although production is much lower, present day prospectors still may pan for gold in California's streams. Gold is used mainly as currency, jewelry, in scientific instruments, and in dental applications.
State Fossil: Saber-Tooth Cat (1973)
California designated the saber-tooth cat (Smilodon californicus) as the official state fossil in 1973. The carnivorous saber-tooth cats (extinct members of the cat family Felidae) flourished throughout North America from the late Eocene and early Oligocene (40 to 35 million years ago) until the close of the Pleistocene about 11,000 years ago. In California, the cat’s fossilized remains are most abundant at the La Brea Tar Pits (late Pleistocene) in Los Angeles where more than 2,500 fossilized specimens have been found. Fossil evidence indicates that this ice age member of the cat family with 8-inch upper canine teeth was somewhat shorter than a modern lion, but weighed more.
Artifact: Chipped Stone Bear (1991)
California also has an official state prehistoric artifact, the chipped stone bear. Discovered at an archaeological dig site in San Diego County in 1985, this small stone object measures about 2 1/2 by 1 1/2 inches and resembles a walking bear. Fashioned from volcanic rock by one of California's earliest inhabitants some 7-8,000 years ago, the stone artifact is thought to have been made for religious use. The Legislature named the chipped stone bear a state symbol in 1991 making California the first state to designate an official State Prehistoric Artifact.
State-specific rockhounding books (including the books listed here as well as other books), regional rockhounding site guides, and other helpful rockhounding resources are identified - by category - in the Books & Gear section of Gator Girl Rocks with a link to the Gator Girl Rocks Amazon Store where you may easily browse selected resources and securely place an order. Your order will benefit Charity Rocks!
U.S. Bureau of Land – California
The BLM manages over fifteen million acres of federal public lands in the state of California.
- Vinson Brown, David Allan, & James Stark, Rocks and Minerals of California (3d ed. 1987).
- David D. Alt & Donald W. Hyndman, Roadside Geology of Northern and Central California (2000).
- Allen F. Glazner & Robert P. Sharp, Geology Underfoot in Southern California (1993).
- Allen F. Glazner & Robert P. Sharp, Geology Underfoot in Death Valley & Owens Valley (1997).
- Allen F. Glazner & Greg Stock, Geology Underfoot in Yosemite National Park (2010).
- James R. Mitchell, Gem Trails of Northern California (2d ed. 2005).
- James R. Mitchell, Gem Trails of Southern California (Rev. ed. 2003).
- Gail A. Butler, Rockhounding California (2d ed. 2012).
- Katherine J. Baylor, California Rocks:A Guide to Geologic Sites in the Golden State (2010).
- Delmer Ross, Rockhounding the Wiley’s Well District of California:The GPS User’s Guide (2006).
- William Estivillo, Gems & Minerals of California:A Guide to Localities (1992).
- B.J. Tegowski, Easy Field Guide to Invertebrate Fossils of California (1995).
- Allan W. Eckert, Earth Treasures Vol. 4A – Southwestern Quadrant (1987; reprint in 2000).
- James Martin Monaco & Jeannette Hathway Monaco, Fee Mining & Rockhounding Adventures in the West (2d ed. 2007).
- Kathy J. Rygle & Stephen F. Pedersen, Southwest Treasure Hunter's Gem & Mineral Guide (4th ed. 2008).
Museums of Interest to Rockhounders
Museum of Los Angeles County
Los Angeles, California
The Museum, located next to the University of Southern California, includes the well known Gem & Mineral Hall, which displays more than 2,000 spectacular specimens and is one of the finest exhibits of gems and minerals in the world. The hall features one of the largest gold exhibits in the world that includes over 300 pounds of natural gold along with gold mining artifacts and other memorabilia. In addition, the museum’s Dinosaur Hall, which is one of the most extraordinary dinosaur exhibits in the world, exhibits more than 300 real fossils and 20 complete dinosaurs and ancient sea creatures.
Rancho La Brea Tar Pits – Los Angeles, California
Rancho La Brea is one of the world’s most famous fossil localities, recognized for having the largest and most diverse assemblage of extinct Ice Age plants and animals in the world. Visitors can learn about Los Angeles as it was between 40,000 and 10,000 years ago, during the last Ice Age, when animals such as saber-tooth cats and mammoths roamed the Los Angeles Basin. Through windows at the Page Museum Laboratory, visitors can watch bones being cleaned and repaired. Outside the Museum, in Hancock Park, life-size replicas of several extinct mammals are featured.
San Diego Natural
San Diego, California
The museum, located in Balboa Park, is one of the oldest in the Western United States. The museum exhibits rocks, minerals, gemstones, and fossils.
University of California Museum of Paleontology
University of California – Berkeley, Berkeley, California
UCMP has the largest paleontological collection of any university museum in the world. A limited number of fossils are exhibited. The museum, however, has online exhibits.
California Academy of Sciences
Golden Gate Park – San Francisco, California
The Academy’s Kimball Natural History Museum exhibits a cast of a Tyrannosaurus rex.
California State Mining & Mineral Museum
The California State Mining & Mineral Museum is a California State Park. The museum’s collection, which began in 1880, contains over 13,000 objects including mining artifacts, rare specimens of crystalline gold in its many forms, as well as beautiful gem and mineral specimens from California and around the world. The museum exhibits the Fricot ‘Nugget,’ a rare and beautiful specimen of crystallized gold discovered in the American River in 1864. This spectacular 13.8-pound specimen is the largest remaining intact mass of crystalline gold from 19th century California.
Fossil Discovery Center of Madera County
The Fossil Discovery Center is across the street from one of the largest middle-Pleistocene fossil excavations in North America. The site was discovered in 1994 when a million-year old Columbian Mammoth tusk was found as workers were scraping dirt at the Madera County landfill in Fairmead. Scientists realized that this County dump was located on one of the most significant fossil beds discovered from the Pleistocene period. In addition to mammoths, fossils have been found from saber tooth cats, giant ground sloths, camels, horses and rare prong-horned antelopes, as well as smaller animals. Thousands of fossils have been recovered from the site.
Raymond M. Alf Museum of Paleontology
The museum’s ‘Hall of Life’ exhibit traces the history of life on earth through exhibits spanning the first cells through human civilization and includes a variety of fossils. In addition, the museum’s ‘Hall of Footprints’ exhibit is the largest, most diverse collection of animal footprints on display in North America and also includes a variety of fossils.
San Bernardino County Museum
The museum exhibits minerals, gemstones, and fossils.
Santa Barbara Museum of Natural History
Santa Barbara, California
The museum’s Geology & paleontology Hall exhibits a variety of fossils including a 19,000-year-old toothed bird, a Miocene giant toothed whale, and the Channel Islands pygmy mammoths. In addition, the museum’s Mineral & Gem Gallery exhibits a variety of minerals, gemstones, and crystals.
Fallbrook Gem & Mineral Society Museum
The museum exhibits rocks, minerals, gemstones, and fossils from San Diego County as well as around the world.
Buena Vista Museum of Natural History
The museum exhibits Miocene fossils from Shark Tooth Hill in Kern County, California.
Boron Twenty Mule Team Museum
The Twenty Mule Team Museum exhibits mining artifacts and historic memorabilia pertaining the history of borax mining in Boron and Death Valley. Borax was first discovered in California in 1881. Borax had been important in small quantities for thousands of years in gold smithing and ceramics.
Borax Visitors Center
North of Boron, California
The Borax Visitor Center looks down on the largest open pit mine in California, measuring one and a half miles long, three quarters of a mile wide, and 650 feet deep. The site, in the Mojave Desert, is one of the biggest and richest deposits of borax on the planet.
Places to Visit - Interesting Sites To See
Lassen Volcanic National Park
Lassen Volcanic National Park’s dominant feature is Lassen Peak, the largest plug dome volcano in the world and the southern-most volcano in the Cascade Range.
Sequoia & Kings Canyon National Parks
Fresno County, California
Sequoia & Kings Canyon National Parks, in addition to including the highest point in the continental 48 states (Mount Whitney), include over 200 caves including California’s longest known cave (Lilburn Cave). The caves, like most caves in the Sierra Nevada of California, are mostly solution caves dissolved from marble. Boyden Cavern, a commercial fee-access karst cavern, also is located within the boundary of the parks.
Death Valley National Park
One interesting mystery of Death Valley National Park is the sliding rocks at Racetrack Playa (a playa is a dry lake bed). These rocks can be found on the floor of the playa with long trails behind them. Somehow these rocks slide across the playa, cutting a furrow in the sediment as they move.
Lava Beds National Monument
Lava Beds National Monument, which lies on the northeastern flank of the Medicine Lake Volcano, is well known for its numerous lava tube caves.
Madera County, California
Devils Postpile National Monument protects and preserves the Devils Postpile formation. The formation is a rare sight in the geologic world and ranks as one of the world’s finest examples of columnar basalt. Its columns tower sixty feet high and display an unusual symmetry.
Pinnacles National Monument is named for a geologic feature – the eroded remains of an extinct volcano.
San Andreas Fault
Named by geologist A.C. Lawson in 1895 for San Andreas Lake, a "sag pond," on the fault trace about 20 miles south of San Francisco (now occupied by one of two reservoirs that are major water storage areas for San Francisco), the San Andreas Fault is the most-studied fault in the world. Two major earthquakes have occurred along the San Andreas Fault in recorded history – the 1857 Fort Tejon earthquake and the 1906 San Francisco earthquake. The fault, which is about 700 miles long extending from Imperial County in southern California northwest to an area of the Pacific Ocean west of the Mendocino County coastline, is the surface manifestation of the boundary between two tectonic plates of the Earth's crust – the Pacific Plate and the North American Plate.
Marshall Gold Discovery State Historic Park
James W. Marshall discovered gold in 1848 on the South Fork of the American River. The gold discovery and ensuing gold rush led to a huge migration of people. The gold discovery site, located in the still visible tailrace of Sutter's sawmill, is one of the most significant historic sites in the nation.
Old Woman Meteorite
Desert Discovery Center – Barstow, California
The Old Woman Meteorite, which weighed just over 6,000 pounds, is the second largest meteorite discovered in the United States. The meteorite was found in 1975 on federal public lands in the Old Woman Mountains in the Needles Resource Area of San Bernardino County, California.
Lassen National Forest – Hat Creek Ranger District
Located near the town of Old Station, the Subway Cave lava tube, which formed about 20,000 years ago, is about 1,300 feet long with a height of six to seventeen feet.
Rockhounding Sites for Children & Families
Federal Public Lands
Bureau of Land Management – Barstow Field Office
The BLM has identified several areas for recreational rockhounding on BLM-managed federal public lands. Subject to federal restrictions, these sites allow recreational rockhounders to collect a variety of specimens including, agate, azurite, borax, calcite, chalcedony, geodes, jasper, lava, olivine, opal, onyx, petrified wood, pyrite, satin spar, travertine, turquoise, and volcanic bombs.
Federal Public Lands
Bureau of Land Management – El Centro Field Office
The BLM has identified several areas for recreational rockhounding on BLM-managed federal public lands. Subject to federal restrictions, the El Centro field office allows recreational rockhounding.
Federal Public Lands
Bureau of Land Management – Hollister Field Office
The BLM has identified several areas for recreational rockhounding on BLM-managed federal public lands. Subject to federal restrictions, these sites allow recreational rockhounders to collect a variety of specimens including, petrified wood and invertebrate fossils.
Federal Public Lands
Bureau of Land Management – Needles Field Office
The BLM has identified several areas for recreational rockhounding on BLM-managed federal public lands. Subject to federal restrictions, these sites allow recreational rockhounders to collect a variety of specimens including, agate, chalcedony, chrysocolla, dolomite, epidote, garnet, geodes, gold, hematite, jasper, limestone, magnetite, marble, opalite, serpentine, and fossils (such as trilobites).
Bureau of Land Management – Mother Lode Field Office
Subject to federal restrictions, the BLM allows low impact gold panning.
Bureau of Land Management – Redding Field Office
Subject to federal restrictions, the BLM allows low impact gold panning.
Agate & Onyx
Jalama Beach County Park – Lompoc, California
Agate and onyx occurs at the beach.
Benitoite Gem Mine – Northwest of Coalinga, California
Commercial (fee access business). Benitoite is the California state gem. The rare gem, however, occurs in very few localities. The business allows rockhounders to collect specimens on weekends.
Jade Cove, California
Jade occurs at the central California coast including Jade Cove. Local beachcombers routinely search for jade pebbles, cobbles, and boulders.
Moonstone Beach – Cambria, California
The ‘moonstones’ here are different than the gemstone. These are cloudy, milky quartz that display well when polished.
Davis Creek, California
Davis Creek/Lassen in northeastern California is the premier obsidian collecting site in California. The site is well known for a variety of obsidian including ‘obsidian needles.’
Pegmatite – Tourmaline
Himalaya Tourmaline Mine – San Diego County, California
Commercial (fee access business). The business allows rockhounders to collect specimens from Himalaya Mine material. The Himalaya Mine is a well known pegmatite locality famous for gem grade tourmaline. The Himalaya Mine is one of several commercial mines located in the famed Pala gem mining district in Southern California. The area, which has been mined for over a century, is famous for its pegmatite minerals including quartz, feldspar, mica, beryl, aquamarine, tourmaline, and kunzite