New Idria District, Diablo Range, San Benito Co., California, USA

A Hg-Cr-gemstone mining area 15 miles long by 9 miles wide, in the southern portion of the Diablo Range.

The deposits are within or along the border of the New Idria serpentine body (serpentinite). The principal ore mineral is cinnabar, with minor amounts of metacinnabar and native mercury. The minerals occur along cracks and veins in Franciscan and Panoche sedimentary rocks that have been hardened by hydrothermal action and in silia-carbonate rock, the hydrothermal alteration of serpentine.

References:
Becker, George F. (1888), Geology of the quicksilver deposits of the Pacific slope: USGS Monograph 13, atlas: 291-309.

Eckel, Edwin Butt & W.B. Myers (1946), Quicksilver deposits of the New Idria district, San Benito and Fresno Counties, California: California Division Mines Report 42: 81-124.

Dickson, F.W. & G. Tunell (1959), Stability relations of cinnabar and metacinnabar: American Mineralogist: 44: 483.

Linn, R.K. and Dietrich, W.F. (1961) Mining and furnacing mercury ore at the New Idria mine, San Benito County, California. US Bureau of Mines Information Circular 8033, 35 pp.

Tunell, G. (1964) Chemical processes in the formation of mercury ores and ores of mercury and antimony. Geochimica et Cosmochimica Acta: 28: 1023.

Mumpton, F.A. Jaffe, H.W., and Thompson, C.S. (1965) Coalingite, a new mineral from the New Idria serpentinite, Fresno and San Benito counties, California. American Mineralogist: 50: 1893-1913.

Davis, F.F. and E.H. Bailey (1966) Mercury. California Division Mines and Geol. Bulletin 191: 252.

Linn, R.K. (1968) New Idria mining district. In: Ore Deposits of the United States, 1933-1967. The Graton-Sales volume, New York, A.I.M.E.: 1633-1649.

Luce, R.W. (1971) Identification of serpentine varieties by infrared absorption. USGS Professional Paper 750-B: 199-201.

Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 120-121, 146.