Laytonville Quarry

Laytonville Quarry is nestled in the Coastal Range of Mendocino County, California, about 5 miles south of the quaint town of Laytonville. This region, part of the Redwood Empire, is renowned for its natural beauty, with nearby redwood forests and the Mendocino National Forest. The quarry’s coordinates are 39° 37' 5'' North, 123° 27' 47'' West, placing it in a scenic area accessible via U.S. Route 101, with nearby towns like Brooktrails, Willits, Covelo, and Cleone.

The quarry is a treasure trove for mineral enthusiasts, boasting 32 valid mineral species. Highlights include aegirine, albite, almandine, aragonite, calcite, chalcopyrite, glaucophane, graphite, ilmenite, jadeite, lawsonite, magnetite, muscovite, pyrite, quartz, riebeckite, siderite, spessartine, talc, titanite, and tremolite. It’s particularly famous as the type locality for deerite, howieite, and zussmanite, rare minerals first described here. The garnets, part of the almandine-spessartine series, often display striking orange-red hues, attracting collectors worldwide.

Geologically, the quarry lies within the Franciscan Formation, a complex of metamorphosed sedimentary and volcanic rocks dating from 252.17 ± 0.06 to 66.0 million years ago. The rocks are primarily blueschist metasediments, formed under high-pressure, low-temperature conditions during tectonic activity. It also includes metabasalt, with minerals like clinozoisite and lawsonite, reflecting the region’s dynamic geological history.

Opened in 1957 by the California Division of Highways, Laytonville Quarry supplied road metal (riprap) for Long Valley Creek’s embankment, producing about 91,000 tons by 1966. Also known as "Longvale" or "Longvale Quarry," it was crucial for infrastructure. Today, it’s no longer actively mined but remains a significant site for mineral collectors and researchers, preserving its historical and scientific value.

Laytonville, near the quarry, is a small town with a population of around 1,152, known for its rural charm and connection to nature. Historically a stagecoach stop in the late 19th century, it’s linked to the Hog Farm, America’s longest-running hippie commune since the 1960s. The town also ties to Anna M. Morrison Reed, a poet, lecturer, and suffragist. Community events like live music and museum exhibitions reflect its vibrant, community-oriented spirit.

The area enjoys a Mediterranean climate, with warm, dry summers averaging 79°F (26°C) and cool, wet winters around 35°F (2°C). Annual precipitation is about 55.9 inches, with February being the wettest. Snow is rare, with trace amounts annually. Surrounded by temperate rainforests, including coast redwoods and Douglas firs, the region supports diverse wildlife like elk and black bears, with the quarry’s geology influencing local water flows and vegetation.