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New Almaden Mining District, Santa Clara County, California, USAi
Regional Level Types
New Almaden Mining DistrictMining District
Santa Clara CountyCounty
CaliforniaState
USACountry

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Latitude & Longitude (WGS84):
37° 10' 36'' North , 121° 50' 44'' West
Latitude & Longitude (decimal):
Mindat Locality ID:
25791
Long-form identifier:
mindat:1:2:25791:1
GUID (UUID V4):
0


A former Hg mining area located in secs. 2 & 3, T9S, R1E, and in secs. 29 & 33, T8S, R1E, MDM, about 12½ miles SSE of San Jose in West-central Santa Clara County. Discovered in 1824 by Antonio Suñol and Louis Chaboya, who mistook native Hg for Ag ore. Land is now owned by the county. Virtually synonymous with the New Almaden Mines, which constitute the bulk of the mining activities in the district.

Local alteration include silica carbonate alteration of serpentine. Local rocks include rocks of the Franciscan Complex, unit 1 (Coast Ranges).

Regional geologic structures include a dominant NW trend and N dip. Local
Local structures include tension fractures and sediment-serpentine contacts. Controls for ore emplacement included the alteration and the tension fractures.

Production statistics: Year: 1964 (period = 1845-1945): 1,137,727 flasks of Hg at 74 pounds/flask were produced (accurate).

Mines: District record includes the mines discussed in Bailey and Everhart's PP-360: New Almaden, America, Providencia, Enriquita, San Antoniao, and San Mateo. The "district" would also include the Guadalupe, Senator, Santa Teresa, and Bernal Mines, however these are likely not of the same deposit.

Select Mineral List Type

Standard Detailed Gallery Strunz Chemical Elements

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.


Mineral List

Mineral list contains entries from the region specified including sub-localities

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

Rock Types Recorded


Rock list contains entries from the region specified including sub-localities

Select Rock List Type

Alphabetical List Tree Diagram

Detailed Mineral List:

'Apophyllite Group'
Formula: AB4[Si8O20]X · 8H2O
Description: Well-developed crystals line crevices in rock.
Aragonite
Formula: CaCO3
Description: Occurs sparingly in the area.
'Aragotite' (FRL)
Formula: (C,H)
Type Locality:
Description: Impregnates siliceous dolomite.
Arsenopyrite
Formula: FeAsS
Description: Minor amounts occur in Hg ore. Bailey & Everhart question this occurrence.
Azurite
Formula: Cu3(CO3)2(OH)2
Baryte ?
Formula: BaSO4
Description: Reported.
Bavenite
Formula: Ca4Be2Al2Si9O26(OH)2
Description: Reported as "Pilinite."
Bornite
Formula: Cu5FeS4
Calcite
Formula: CaCO3
Chalcopyrite
Formula: CuFeS2
Chromite
Formula: Fe2+Cr3+2O4
Chrysocolla
Formula: Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
Description: Occurs as pseudomorphs after cuprite.
Cinnabar
Formula: HgS
Localities: Reported from at least 24 localities in this region.
Dolomite
Formula: CaMg(CO3)2
Localities: Reported from at least 8 localities in this region.
Epsomite
Formula: MgSO4 · 7H2O
Description: Abundant on mine walls as a post-mining product.
Fluorite
Formula: CaF2
Colour: White
Description: Occurs as crystals.
Galena
Formula: PbS
Glaucophane
Formula: ◻Na2(Mg3Al2)Si8O22(OH)2
Description: Occurs as glaucophane schist.
Gyrolite
Formula: NaCa16Si23AlO60(OH)8 · 14H2O
Jarosite
Formula: KFe3+3(SO4)2(OH)6
Malachite
Formula: Cu2(CO3)(OH)2
Metacinnabar
Formula: HgS
Millerite
Formula: NiS
Description: Occurs in Hg ores.
Native Mercury
Formula: Hg
Localities: Reported from at least 6 localities in this region.
Opal
Formula: SiO2 · nH2O
'Petroleum var. Bitumen'
Pyrite
Formula: FeS2
Quartz
Formula: SiO2
Localities: Reported from at least 9 localities in this region.
Quartz var. Chalcedony
Formula: SiO2
'Serpentine Subgroup'
Formula: D3[Si2O5](OH)4
Localities: Reported from at least 20 localities in this region.
Sphalerite
Formula: ZnS
Stibnite
Formula: Sb2S3
Stilpnomelane
Formula: K4Fe2+48[Si64Al8]O164(OH)52 · nH2O
Description: Occurs in glaucophane schist.
Tiemannite
Formula: HgSe
Zaratite
Formula: Ni3(CO3)(OH)4 · 4H2O ?
Description: A minor mineral in the district.

Gallery:

List of minerals arranged by Strunz 10th Edition classification

Group 1 - Elements
Native Mercury1.AD.05Hg
Group 2 - Sulphides and Sulfosalts
Bornite2.BA.15Cu5FeS4
Metacinnabar2.CB.05aHgS
Sphalerite2.CB.05aZnS
Tiemannite2.CB.05aHgSe
Chalcopyrite2.CB.10aCuFeS2
Millerite2.CC.20NiS
Galena2.CD.10PbS
Cinnabar2.CD.15aHgS
Stibnite2.DB.05Sb2S3
Pyrite2.EB.05aFeS2
Arsenopyrite2.EB.20FeAsS
Group 3 - Halides
Fluorite3.AB.25CaF2
Group 4 - Oxides and Hydroxides
Chromite4.BB.05Fe2+Cr3+2O4
Quartz
var. Chalcedony
4.DA.05SiO2
4.DA.05SiO2
Opal4.DA.10SiO2 · nH2O
Group 5 - Nitrates and Carbonates
Calcite5.AB.05CaCO3
Dolomite5.AB.10CaMg(CO3)2
Aragonite5.AB.15CaCO3
Azurite5.BA.05Cu3(CO3)2(OH)2
Malachite5.BA.10Cu2(CO3)(OH)2
Zaratite5.DA.15Ni3(CO3)(OH)4 · 4H2O ?
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Baryte ?7.AD.35BaSO4
Jarosite7.BC.10KFe3+3(SO4)2(OH)6
Epsomite7.CB.40MgSO4 · 7H2O
Group 9 - Silicates
Glaucophane9.DE.25◻Na2(Mg3Al2)Si8O22(OH)2
Bavenite9.DF.25Ca4Be2Al2Si9O26(OH)2
Chrysocolla9.ED.20Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
Gyrolite9.EE.30NaCa16Si23AlO60(OH)8 · 14H2O
Stilpnomelane9.EG.40K4Fe2+48[Si64Al8]O164(OH)52 · nH2O
Unclassified
'Apophyllite Group'-AB4[Si8O20]X · 8H2O
'Aragotite' (TL)-(C,H)
'Petroleum
var. Bitumen'
-
'Serpentine Subgroup'-D3[Si2O5](OH)4

List of minerals for each chemical element

HHydrogen
H Apophyllite GroupAB4[Si8O20]X · 8H2O
H Aragotite(C,H)
H AzuriteCu3(CO3)2(OH)2
H BaveniteCa4Be2Al2Si9O26(OH)2
H ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
H EpsomiteMgSO4 · 7H2O
H Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
H GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
H JarositeKFe33+(SO4)2(OH)6
H MalachiteCu2(CO3)(OH)2
H OpalSiO2 · nH2O
H StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
H ZaratiteNi3(CO3)(OH)4 · 4H2O ?
H Serpentine SubgroupD3[Si2O5](OH)4
BeBeryllium
Be BaveniteCa4Be2Al2Si9O26(OH)2
CCarbon
C AragoniteCaCO3
C Aragotite(C,H)
C AzuriteCu3(CO3)2(OH)2
C CalciteCaCO3
C DolomiteCaMg(CO3)2
C MalachiteCu2(CO3)(OH)2
C ZaratiteNi3(CO3)(OH)4 · 4H2O ?
OOxygen
O Apophyllite GroupAB4[Si8O20]X · 8H2O
O AragoniteCaCO3
O AzuriteCu3(CO3)2(OH)2
O BaryteBaSO4
O BaveniteCa4Be2Al2Si9O26(OH)2
O CalciteCaCO3
O Quartz var. ChalcedonySiO2
O ChromiteFe2+Cr23+O4
O ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
O DolomiteCaMg(CO3)2
O EpsomiteMgSO4 · 7H2O
O Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
O GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
O JarositeKFe33+(SO4)2(OH)6
O MalachiteCu2(CO3)(OH)2
O OpalSiO2 · nH2O
O QuartzSiO2
O StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
O ZaratiteNi3(CO3)(OH)4 · 4H2O ?
O Serpentine SubgroupD3[Si2O5](OH)4
FFluorine
F FluoriteCaF2
NaSodium
Na Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
Na GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
MgMagnesium
Mg DolomiteCaMg(CO3)2
Mg EpsomiteMgSO4 · 7H2O
Mg Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
AlAluminium
Al BaveniteCa4Be2Al2Si9O26(OH)2
Al ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
Al Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
Al GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
Al StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
SiSilicon
Si Apophyllite GroupAB4[Si8O20]X · 8H2O
Si BaveniteCa4Be2Al2Si9O26(OH)2
Si Quartz var. ChalcedonySiO2
Si ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
Si Glaucophane◻Na2(Mg3Al2)Si8O22(OH)2
Si GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
Si OpalSiO2 · nH2O
Si QuartzSiO2
Si StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
Si Serpentine SubgroupD3[Si2O5](OH)4
SSulfur
S ArsenopyriteFeAsS
S BaryteBaSO4
S BorniteCu5FeS4
S ChalcopyriteCuFeS2
S CinnabarHgS
S EpsomiteMgSO4 · 7H2O
S GalenaPbS
S JarositeKFe33+(SO4)2(OH)6
S MetacinnabarHgS
S MilleriteNiS
S PyriteFeS2
S SphaleriteZnS
S StibniteSb2S3
KPotassium
K JarositeKFe33+(SO4)2(OH)6
K StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
CaCalcium
Ca AragoniteCaCO3
Ca BaveniteCa4Be2Al2Si9O26(OH)2
Ca CalciteCaCO3
Ca DolomiteCaMg(CO3)2
Ca FluoriteCaF2
Ca GyroliteNaCa16Si23AlO60(OH)8 · 14H2O
CrChromium
Cr ChromiteFe2+Cr23+O4
FeIron
Fe ArsenopyriteFeAsS
Fe BorniteCu5FeS4
Fe ChalcopyriteCuFeS2
Fe ChromiteFe2+Cr23+O4
Fe JarositeKFe33+(SO4)2(OH)6
Fe PyriteFeS2
Fe StilpnomelaneK4Fe482+[Si64Al8]O164(OH)52 · nH2O
NiNickel
Ni MilleriteNiS
Ni ZaratiteNi3(CO3)(OH)4 · 4H2O ?
CuCopper
Cu AzuriteCu3(CO3)2(OH)2
Cu BorniteCu5FeS4
Cu ChalcopyriteCuFeS2
Cu ChrysocollaCu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1
Cu MalachiteCu2(CO3)(OH)2
ZnZinc
Zn SphaleriteZnS
AsArsenic
As ArsenopyriteFeAsS
SeSelenium
Se TiemanniteHgSe
SbAntimony
Sb StibniteSb2S3
BaBarium
Ba BaryteBaSO4
HgMercury
Hg CinnabarHgS
Hg Native MercuryHg
Hg MetacinnabarHgS
Hg TiemanniteHgSe
PbLead
Pb GalenaPbS

Other Databases

Link to USGS MRDS:60000981

Localities in this Region

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate
USA

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