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New Almaden Mine (New Almaden Mines), Almaden Quicksilver County Park, New Almaden, New Almaden District, Santa Cruz Mts, Santa Clara Co., California, USA

This page kindly sponsored by Michael Cox
Latitude & Longitude (WGS84): 37° 10' 37'' North , 121° 50' 20'' West
Latitude & Longitude (decimal): 37.17694,-121.83889
Köppen climate type:Csb : Warm-summer Mediterranean climate

A former Hg mine complex located in secs. 2 & 3, T9S, R1E, and in secs. 29 & 33, T8S, R1E, MDM, 100 feet E of New Almaden and about 12½ miles SSE of San Jose. Discovered in 1824 by Antonio Suñol and Louis Chaboya.

Mineralization is a Hg deposit hosted in siliceous dolomite.

Production for the group was more than 1,000,000 flasks of Hg, most from this mine.

Mineral List

16 valid minerals. 1 (FRL) - first recorded locality of unapproved mineral/variety/etc.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on

Cretaceous - Jurassic
66 - 201.3 Ma

ID: 2890365
Franciscan Complex, unit 1 (Coast Ranges)

Age: Mesozoic (66 - 201.3 Ma)

Stratigraphic Name: Franciscan Complex; Dothan Formation; Honda Formation; San Luis Formation; Valentine Spring Formation

Description: Franciscan complex: Cretaceous and Jurassic sandstone with smaller amounts of shale, chert, limestone, and conglomerate. Includes Franciscan melange, except where separated--see KJfm.

Comments: Coast Ranges. Primarily Yolla Bolly, Central, and San Simeon terranes of Silberling et al. (1987). Consists primarily of variably deformed and metamorphosed graywacke, mudstone, and chert.

Lithology: Major:{sandstone,mudstone}, Minor:{chert}, Incidental:{limestone, conglomerate, greenstone, serpentinite, gabbro, amphibolite, schist, felsic volcanic}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Early Jurassic
174.1 - 201.3 Ma

ID: 2588897
Franciscan Complex Central Belt, Basaltic volcanic rocks of Marin Headlands terrane

Age: Early Jurassic (174.1 - 201.3 Ma)

Description: Basaltic flows, massive to pillowed, locally vesicular, with minor tuff and pillow breccia. Geochemistry suggests a mid-ocean ridge (MORB) or an off-ridge origin. Age is late Early Jurassic (Pliensbachian) or older, based on age of overlying radiolarian cherts.

Comments: New Almaden Block

Reference: Wentworth, C.M., M.C. Blake Jr., R.J. McLaughlin, R.W. Graymer. Preliminary Geologic Map of the San Jose 30 X 60 Minute Quadrangle, California. U.S. Geological Survey Open-File Report 98-795. [91]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Blake, Wm. P. (1854), Quicksilver mine of Almaden, California: American Journal of Science, 2nd. Series: 17: 438-440.
Durand, F.E. (1873), Description of a new mineral from the New Almaden mine: California Academy of Science Proceedings: 4: 218.
Hanks, Henry Garber (1884), Fourth report of the State Mineralogist: California Mining Bureau. Report 4, 410 pp. (includes catalog of minerals of California pp. 63-410), and miscellaneous observations on mineral products): 289.
Jackson, Abraham Wendell, Jr. (1886), Mineralogical contributions: California Academy of Science, 1st. series, Bulletin 4: 358-374; […(abstract): Neues Jahrb., 1888: 179-181]: 371.
Clarke, F.W. (1889), A new occurrence of gyrolite: USGS Bulletin 64: 22-23; […American Journal of Science, 3rd. series: 38: 128-129]: 22 (128-129).
Irelan, William, Jr. (1890a), Ninth annual report of the State Mineralogist: California Mining Bureau. Report 9, 352 pp.: 47.
Melville, William Harlow (1890), Metacinnabarite from New Almaden, California: American Journal of Science, 3rd. series: 40: 291-295.
Melville, William Harlow (1891), Metacinnabarite from New Almaden, California: USGS Bulletin 78: 80-83.
Dana, Edward Salisbury (1892), System of mineralogy, 6th. ed., 1134 pp., Wiley & Sons, New York: 1095.
Randol, J.B. (1892), Quicksilver: US Census Report 11, Mineral Industries in the U.S.: 180.
Hanks, Henry Garber (1905), Notes on “aragotite,” a rare California mineral: Royal Micr. Soc. Jour., 1905: 673-676.
Bradley, W.W. (1918), Quicksilver resources of California, with a section on metallurgy and ore dressing: California Mining Bureau. Bulletin 78, 389 pp.: 154, 191.
Huguenin, Emile & W.O. Castello (1921), Alameda, Contra Costa, San Francisco, San Mateo, Santa Clara, Santa Cruz Counties: California Mining Bureau. Report 17: 222.
Bailey, Edgar H. & Donald L. Everhart (1964), Geology and quicksilver deposits of the New Almaden district, Santa Clara County, California: USGS PP 360: 96, 97, 98, 99, 102.
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 81, 83, 87, 134, 145, 172, 179, 191, 212, 233, 260, 266, 302.
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 65, 73, 131, 221, 445, 478.

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