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East Foothills, Black Wonder Mining District, Santa Clara County, California, USAi
Regional Level Types
East Foothills- not defined -
Black Wonder Mining DistrictMining District
Santa Clara CountyCounty
CaliforniaState
USACountry

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PhotosMapsSearchMineralogy
07924470017272011464712.jpg
Alum Rock Park "Meteor" (pre-1918)

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
09146390017271924183007.jpg
Kempite, etc.

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
05913100017272055258795.jpg
Hausmannite

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
07924470017272011464712.jpg
Alum Rock Park "Meteor" (pre-1918)

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
09146390017271924183007.jpg
Kempite, etc.

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
05913100017272055258795.jpg
Hausmannite

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
07924470017272011464712.jpg
Alum Rock Park "Meteor" (pre-1918)

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
09146390017271924183007.jpg
Kempite, etc.

Mn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
Latitude & Longitude (WGS84):
37° 22' 51'' North , 121° 49' 2'' West
Latitude & Longitude (decimal):
37.38111,-121.81750
GRN:
N25W70
Köppen climate type:
Csb : Warm-summer Mediterranean climate
Nearest Settlements:
PlacePopulationDistance
East Foothills8,269 (2011)0.0km
Alum Rock15,536 (2018)1.9km
San Jose1,026,908 (2017)8.3km
Milpitas77,604 (2017)9.5km
Seven Trees1,788 (2018)10.7km
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
ClubLocationDistance
Santa Clara Valley Gem & Mineral SocietySan Jose, California8km
Peninsula Gem & Geology Society, Inc.Los Altos, California26km
Livermore Valley LithophilesLivermore, California34km
Sequoia Gem and Mineral SocietyRedwood City, California39km
Mineral & Gem Society of Castro ValleyHayward, California40km
Mindat Locality ID:
227084
Long-form identifier:
mindat:1:2:227084:8
GUID (UUID V4):
0


A populated place (town) located E of Alum Rock (town), along the western foothills of the Diablo Range.

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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

12 valid minerals. 1 (TL) - type locality of valid minerals.

Rock Types Recorded


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

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Alphabetical List Tree Diagram

Detailed Mineral List:

ⓘ Alabandite
Formula: MnS
ⓘ Alleghanyite
Formula: Mn2+5(SiO4)2(OH)2
ⓘ Baryte
Formula: BaSO4
Description: Occurred as crystals of unusual habit in seams in the Mn-boulder.
ⓘ Ganophyllite
Formula: (K,Na)xMn2+6(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Colour: Brownish yellow
Description: Occurs as tabular crystals in seams with baryte.
ⓘ Hausmannite
Formula: Mn2+Mn3+2O4
Description: Abundant as crystals and subhedral grains.
ⓘ Hydromagnesite
Formula: Mg5(CO3)4(OH)2 · 4H2O
Description: Occurs as spherical nodules of finely crystalline material up to 4 cm in diameter in serpentine.
ⓘ Kempite (TL)
Formula: Mn2+2(OH)3Cl
Type Locality:
Colour: Green
Description: Minute crystals.
ⓘ Laumontite
Formula: CaAl2Si4O12 · 4H2O
ⓘ 'Manganese Oxides'
ⓘ 'Psilomelane'
Description: Formed the dark outer rim of the boulder.
ⓘ Pyrochroite
Formula: Mn(OH)2
ⓘ Quartz
Formula: SiO2
ⓘ Rhodochrosite
Formula: MnCO3
Description: Crystals with unusual, unspecified, crystal faces.
ⓘ 'Serpentine Subgroup'
Formula: D3[Si2O5](OH)4
ⓘ Tephroite ?
Formula: Mn2+2(SiO4)
Habit: massive
Colour: Grayish red
Description: Tephroite reported by Rogers is most likely alleghanyite, as per the comments in the type locality description of alleghanyite published in "Ross, Clarence Samuel & Paul F. Kerr (1932), Manganese mineral of a vein near Bald Knob, North Carolina: American Mineralogist: 17: 1-18". A new analysis is needed to confirm.
References:
Rogers, Austin Flint (1919) An interesting occurrence of manganese minerals near San Jose, California. American Journal Of Science, S. 4 Vol. 48. 443-449p.444
Rogers, Austin Flint (1924): Kempite, a new manganese mineral from Santa Clara County, California. American Journal of Science, 5th. Series: 8: 145-150.
[…(abstract): Geological Society of America Bulletin: 36: 206 (1925)]: 206
Ross, Clarence S., Kerr, Paul F. (1932) The manganese minerals of a vein near Bald Knob, North Carolina. American Mineralogist, 17 (1) 1-18 p.13
Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 59, 362
Pemberton, H. Earl (1983) Minerals of California. Van Nostrand Reinhold Company Inc.
www.mineralsocal.org (1999) https://www.mineralsocal.org
(2005) Mineral Resources Data System (MRDS), US Geological Survey.

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
ⓘAlabandite2.CD.10MnS
Group 3 - Halides
ⓘKempite (TL)3.DA.10aMn2+2(OH)3Cl
Group 4 - Oxides and Hydroxides
ⓘHausmannite4.BB.10Mn2+Mn3+2O4
ⓘQuartz4.DA.05SiO2
ⓘPyrochroite4.FE.05Mn(OH)2
Group 5 - Nitrates and Carbonates
ⓘRhodochrosite5.AB.05MnCO3
ⓘHydromagnesite5.DA.05Mg5(CO3)4(OH)2 · 4H2O
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
ⓘBaryte7.AD.35BaSO4
Group 9 - Silicates
ⓘTephroite ?9.AC.05Mn2+2(SiO4)
ⓘAlleghanyite9.AF.45Mn2+5(SiO4)2(OH)2
ⓘGanophyllite9.EG.30(K,Na)xMn2+6(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
ⓘLaumontite9.GB.10CaAl2Si4O12 · 4H2O
Unclassified
ⓘ'Psilomelane'-
ⓘ'Serpentine Subgroup'-D3[Si2O5](OH)4
ⓘ'Manganese Oxides'-

List of minerals for each chemical element

HHydrogen
Hⓘ AlleghanyiteMn52+(SiO4)2(OH)2
Hⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Hⓘ HydromagnesiteMg5(CO3)4(OH)2 · 4H2O
Hⓘ KempiteMn22+(OH)3Cl
Hⓘ LaumontiteCaAl2Si4O12 · 4H2O
Hⓘ PyrochroiteMn(OH)2
Hⓘ Serpentine SubgroupD3[Si2O5](OH)4
CCarbon
Cⓘ HydromagnesiteMg5(CO3)4(OH)2 · 4H2O
Cⓘ RhodochrositeMnCO3
OOxygen
Oⓘ AlleghanyiteMn52+(SiO4)2(OH)2
Oⓘ BaryteBaSO4
Oⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Oⓘ HausmanniteMn2+Mn23+O4
Oⓘ HydromagnesiteMg5(CO3)4(OH)2 · 4H2O
Oⓘ KempiteMn22+(OH)3Cl
Oⓘ LaumontiteCaAl2Si4O12 · 4H2O
Oⓘ PyrochroiteMn(OH)2
Oⓘ QuartzSiO2
Oⓘ RhodochrositeMnCO3
Oⓘ TephroiteMn22+(SiO4)
Oⓘ Serpentine SubgroupD3[Si2O5](OH)4
NaSodium
Naⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
MgMagnesium
Mgⓘ HydromagnesiteMg5(CO3)4(OH)2 · 4H2O
AlAluminium
Alⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Alⓘ LaumontiteCaAl2Si4O12 · 4H2O
SiSilicon
Siⓘ AlleghanyiteMn52+(SiO4)2(OH)2
Siⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Siⓘ LaumontiteCaAl2Si4O12 · 4H2O
Siⓘ QuartzSiO2
Siⓘ TephroiteMn22+(SiO4)
Siⓘ Serpentine SubgroupD3[Si2O5](OH)4
SSulfur
Sⓘ AlabanditeMnS
Sⓘ BaryteBaSO4
ClChlorine
Clⓘ KempiteMn22+(OH)3Cl
KPotassium
Kⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
CaCalcium
Caⓘ LaumontiteCaAl2Si4O12 · 4H2O
MnManganese
Mnⓘ AlabanditeMnS
Mnⓘ AlleghanyiteMn52+(SiO4)2(OH)2
Mnⓘ Ganophyllite(K,Na)xMn62+(Si,Al)10O24(OH)4 · nH2O (x = 1-2; n = 7-11)
Mnⓘ HausmanniteMn2+Mn23+O4
Mnⓘ KempiteMn22+(OH)3Cl
Mnⓘ PyrochroiteMn(OH)2
Mnⓘ RhodochrositeMnCO3
Mnⓘ TephroiteMn22+(SiO4)
BaBarium
Baⓘ BaryteBaSO4

Localities in this Region

USA
USA

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate
USA

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