San Benito Mountain

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San Benito Mountain
San Benito Mountain is located in California
San Benito Mountain
San Benito Mountain
Location in California
Elevation 5,267 ft (1,605 m) NAVD 88[1]
Prominence 3,481 ft (1,061 m)[2]
Listing California County High Points[2]
Location San Benito County, California, U.S.
Range Diablo Range
Coordinates 36°22′10″N 120°38′41″W / 36.369579269°N 120.644657844°W / 36.369579269; -120.644657844Coordinates: 36°22′10″N 120°38′41″W / 36.369579269°N 120.644657844°W / 36.369579269; -120.644657844[1]
Topo map USGS San Benito Mountain

San Benito Mountain is a mountain located in the Diablo Range of California. The mountain, which rises to an elevation of 5,267 feet (1,605 m), is the highest point in San Benito County and the Diablo Range.[2] The mountain gets some snowfall during winter.[3]

The Clear Creek Management Area, which encompasses the San Benito Mountain Research Natural Area, has been subject to a temporary closure by the BLM since May 2008 due to concerns of visitor exposure to naturally occurring asbestos (chrysotile).[4] The area was a major OHV riding area prior to the closure. The core area of the Clear Creek Management Area (approximately 35,000 acres) is the New Idria serpentine mass. The serpentine is highly sheared/pulverized and contains abundant chrysotile asbestos.

Extreme shearing of the bedrock, combined with soil nutrient imbalances, has resulted in extensive areas of natural barrens completely devoid of vegetation. The serpentine soils harbor several rare plant species, including the Federally listed Threatened San Benito evening primrose (Camissonia benitensis). A unique pine and incense cedar forest occurs at the highest elevations of the mountain.

The serpentine mass contains two superfund sites, Atlas Mine and Johns-Mansville. Both were associated with the mining and processing of chrysotile asbestos. Other minerals mined from the serpentine mass included cinnabar, chromite, magnesite, and jadeite. The Gem mine (private) located within the serpentine mass is the only source of gem-grade benitoite in the world. The rare minerals neptunite and joaquinite have also been found there.


  1. ^ a b "5258". NGS data sheet. U.S. National Geodetic Survey. 
  2. ^ a b c "San Benito Mountain, California". 
  3. ^ "Subsection M262Ac - Diablo Range". U.S. Forest Service. Archived from the original on 2005-03-15. Retrieved 2014-02-22. 
  4. ^ "Clear Creek Management Area". Bureau of Land Management. Retrieved 2009-12-22. 

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