|Latitude & Longitude (WGS84):||37° 10' 36'' North , 121° 50' 20'' West|
|Latitude & Longitude (decimal):||37.17694,-121.83889|
|Köppen climate type:||Csb : Warm-summer Mediterranean climate|
A former Hg occurrence/mine complex located in secs. 2 & 3, T9S, R1E, and in secs. 29 & 33, T8S, R1E, MDM, 1.6 km (1.0 mile) W of New Almaden and about 12½ miles SSE of San Jose, on Victoria shaft, near the top of Mine Hill, on county owned land (Almaden Quicksilver County Park). Discovered in 1824 by Antonio Suñol and Louis Chaboya. First produced in 1845. MRDS database stated accuracy for this location is 1,000 meters. The property was sold by New Idria Mining and Chemical Company to Santa Clara County in 1975. The area is now the Almaden Quicksilver Park.
Mineralization is a Hg deposit hosted in Late Cretaceous serpentinite and tuff. The ore body strikes and dips N55W:45E and is irregular with a depth-to-bottom of 731.52 meters. Ore body No. 1 is a replacement body with an irregular shape. Ore body No. 2 is a tabular body in a fissure vein. The primary mode of origin was hydrothermal activity. Primary ore control was lithology (serpentine-tuff contact) and the secondary control was fracturing. Wallrock alteration is moderate (carbonitization). Associated with Upper Cretaceous rocks of the Santa Teresa Hills. Local rocks include rocks of the Franciscan Complex, unit 1 (Coast Ranges).
Local geologic structures include a local anticline and tension fractures. Regional structure is NW-trending.
Workings include surface and underground openings with a length of 53,106.9 meters and an overall depth of 746.76 meters (cumulative all mines).
Production to the end of 1976 was 38,090,000 kilograms (1,104,922 flasks) of Hg from 1,722,900 tonnes of ore. The average 5 year annual grade was 5.40% and the cumulative grade was 2.21%. Production for the group was more than 1,000,000 flasks of Hg, most from this mine.
Estimates of hypothetical resources range from 100,000 to 1,000,000 flasks of Hg.
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
16 valid minerals. 1 (FRL) - first recorded locality of unapproved mineral/variety/etc.
Rock Types Recorded
Note: this is a very new system on mindat.org and data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
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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.
Forstner, W. (1908), Quicksilver Resources of California, California Division of Mines and Geology Bulletin 27, 270 pp.
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.
Franke, Herbert A. (1930), Santa Clara, Nevada, Kings, Tulare Counties: California Mining Bureau (Report 26): 26: 26-33.
Ransome, Alfred Leslie & J.L. Kellogg (1939), Quicksilver resources of California: California Journal of Mines and Geology, California Division Mines (Report 35): 35: 353-486.
U.S. Bureau of Mines staff (1943), New Almaden Mine, Santa Clara County, California, U.S. Bureau of Mines War Minerals Report WMR 203, 11 pp.
Bedford, R.H. and Ricker, S. (1950), Investigation of the New Almaden Mercury Mine, Santa Clara County, California, U.S. Bureau of Mines Report of Investigation RI 4697, 29 pp.
Bailey, Edgar H. (1951), New Almaden quicksilver mine: California Division Mines Bulletin 154: 263-270.
Bailey, Edgar H. (1952), Suggestions for Exploration at New Almaden Quicksilver Mine, California, California Division of Mines Special Report 17, 4 pp.
Davis, Fenelon Francis & C.W. Jennings (1954), Mines and mineral resources of Santa Clara County, California: California Journal of Mines and Geology (Report 50): 50(2): 342-354.
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.
Holmes, Jr., G.W. (1965), Mercury in California: in: U.S. Bureau of Mines Information Circular 8252.
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.
Cargill, S. M., Root, D. H. and Bailey, Edgar H. (1980), Resource Estimation from Historical DAta - Mercury, A Test Case: International Association Mathematical Geology Journal: 12(5): 489-522.
Drake, Harold J. (1980), Mercury; Mineral Facts and Problems, U.S. Bureau of Mines Bulletin 671: 563-574.
De Young, John H. (1981), The Lasky Cummulative Tonnage-Grade Relationship - A Reexamination, Ecoinomic geology: 76: 1067-1080.
Cargill, S. M., Root, D. H. and Bailey, Edgar H. (1981), Estimating Usable Resources from Historical Industry DAta, Economic geology: 76: 1081-1095.
Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 65, 73, 131, 221, 445, 478.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10040742.
Bailey, Edgar H., USGS, personal files.