Mendenhall No. 1 Mine (Cedar Mountain Mine; Mendenhall Chrome Mines; Mendenhall Mine; Newman Mine), Cedar Mountain, Cedar Mountain Mining District, Alameda County, California, USAi
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Latitude & Longitude (WGS84):
37° 33' 26'' North , 121° 36' 42'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Livermore | 88,126 (2017) | 19.5km |
| Sunol | 913 (2011) | 24.7km |
| Mountain House | 9,675 (2011) | 25.8km |
| Pleasanton | 79,510 (2017) | 25.9km |
| Tracy | 87,075 (2017) | 26.0km |
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
Local clubs are the best way to get access to collecting localities
| Club | Location | Distance |
|---|---|---|
| Livermore Valley Lithophiles | Livermore, California | 19km |
| Santa Clara Valley Gem & Mineral Society | San Jose, California | 35km |
| Mineral & Gem Society of Castro Valley | Hayward, California | 43km |
| East Bay Mineral and Lapidary Club | Hayward, California | 44km |
| Peninsula Gem & Geology Society, Inc. | Los Altos, California | 48km |
A former Cr occurrence/mine located in the NE¼NW¼SE¼ sec. 26 & in secs. 27 & 35, T4S, R3E, MDM, 0.6 km (0.4 mile; 2,100 feet) WSW of Cedar Mountain summit (coordinates of record), on Cedar Mountain Ridge, on private land (fee ownership). Discovered in 1882. Owned by Vernon E. and Dorothy Rose (100%), Livermore, California (1976). Operated by the Palo Alto Mining Corporation, Campbell, California (1956- ). Gerard M. And Marie T. Lafon May Own A portion of the mine area. First production occurred in 1885 and the last in 1956. MRDS database stated accuracy for this location is 1,000 meters.
Mineralization is hosted in serpentinite. The ore body strikes N00W and dips 30N with a depth-to-top of 0.0 meters. A nearly circular mass of serpentinized ultramafic rocks, about 1 mile (1.6 km) in diameter, occur on Cedar Mountain. Ore body No. 1 is a fissure vein & tabular. Ore Body No. 2 is a shear zone and irregular. Ore body No. 3 is disseminated. The primary mode of origin was magmatic differentiation. The secondary mode of origin was other. Primary ore control was lithology while secondary control, was fracturing. Ore occurs in irregular, lenticular pockets and stringers. Wallrock alteration is intense (carbonitization). Local rocks include ultramafic rocks, chiefly Mesozoic, unit 3 (Coast Ranges and Western Klamath Mountains) and/or rocks of the Franciscan Complex, unit 1 (Coast Ranges).
Workings include surface and underground openings with an overall length of 91.44 meters and an overall width of 30.48 meters and comprised of several large, open cuts and trenches.
Production data are found in: Stinson, Melvin Clarence (1975).
Significant production occurred from this mine during the period 1953 to 1956 although no data on reserves is available. Concentrates from this period ran 43.3 to 51.3% Cr2O3, 11.7% Fe and 2.5:3.0 Cr:Fe ratio. Analysis by the California Division Mines & Geology in 1976 gave the following percentages: massive 2: 18.50%, Cr2O3: 36.54%, FeO: 9.62%, total Fe: 12.87%, Al2O3: 5.80%, Cr:Fe = 2.50.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsCommodity List
This is a list of exploitable or exploited mineral commodities recorded at this locality.Mineral List
7 valid minerals. 1 erroneous literature entry.
Rock Types Recorded
Note: data is currently VERY limited. Please bear with us while we work towards adding this information!
Select Rock List Type
Alphabetical List Tree DiagramDetailed Mineral List:
| ⓘ Albite Formula: Na(AlSi3O8) Description: Occurs as glassy material. References: |
| ⓘ Antigorite Formula: Mg3(Si2O5)(OH)4 |
| ⓘ Formula: Fe2+Cr3+2O4 |
| ⓘ Chrysotile Formula: Mg3(Si2O5)(OH)4 |
| ⓘ Clinochlore Formula: Mg5Al(AlSi3O10)(OH)8 |
| ⓘ Clinochlore var. Chromium-bearing Clinochlore Formula: Mg5(Al,Cr)2Si3O10(OH)8 |
| ⓘ Magnesiochromite Formula: MgCr2O4 |
| ⓘ Quartz Formula: SiO2 Colour: Yellow Description: Occurs as crystals. References: |
| ⓘ 'Serpentine Subgroup' Formula: D3[Si2O5](OH)4 |
| ⓘ Uvarovite Formula: Ca3Cr2(SiO4)3 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Chromite ? | 4.BB.05 | Fe2+Cr3+2O4 |
| ⓘ | Magnesiochromite | 4.BB.05 | MgCr2O4 |
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 9 - Silicates | |||
| ⓘ | Chrysotile | 9.00. | Mg3(Si2O5)(OH)4 |
| ⓘ | Uvarovite | 9.AD.25 | Ca3Cr2(SiO4)3 |
| ⓘ | Clinochlore | 9.EC.55 | Mg5Al(AlSi3O10)(OH)8 |
| ⓘ | var. Chromium-bearing Clinochlore | 9.EC.55 | Mg5(Al,Cr)2Si3O10(OH)8 |
| ⓘ | Antigorite | 9.ED.15 | Mg3(Si2O5)(OH)4 |
| ⓘ | Albite | 9.FA.35 | Na(AlSi3O8) |
| Unclassified | |||
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Antigorite | Mg3(Si2O5)(OH)4 |
| H | ⓘ Chrysotile | Mg3(Si2O5)(OH)4 |
| H | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| H | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| O | Oxygen | |
| O | ⓘ Albite | Na(AlSi3O8) |
| O | ⓘ Antigorite | Mg3(Si2O5)(OH)4 |
| O | ⓘ Chrysotile | Mg3(Si2O5)(OH)4 |
| O | ⓘ Chromite | Fe2+Cr23+O4 |
| O | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| O | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| O | ⓘ Magnesiochromite | MgCr2O4 |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Na | Sodium | |
| Na | ⓘ Albite | Na(AlSi3O8) |
| Mg | Magnesium | |
| Mg | ⓘ Antigorite | Mg3(Si2O5)(OH)4 |
| Mg | ⓘ Chrysotile | Mg3(Si2O5)(OH)4 |
| Mg | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Mg | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| Mg | ⓘ Magnesiochromite | MgCr2O4 |
| Al | Aluminium | |
| Al | ⓘ Albite | Na(AlSi3O8) |
| Al | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Al | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| Si | Silicon | |
| Si | ⓘ Albite | Na(AlSi3O8) |
| Si | ⓘ Antigorite | Mg3(Si2O5)(OH)4 |
| Si | ⓘ Chrysotile | Mg3(Si2O5)(OH)4 |
| Si | ⓘ Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| Si | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| Si | ⓘ Quartz | SiO2 |
| Si | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Ca | Calcium | |
| Ca | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Cr | Chromium | |
| Cr | ⓘ Chromite | Fe2+Cr23+O4 |
| Cr | ⓘ Clinochlore var. Chromium-bearing Clinochlore | Mg5(Al,Cr)2Si3O10(OH)8 |
| Cr | ⓘ Magnesiochromite | MgCr2O4 |
| Cr | ⓘ Uvarovite | Ca3Cr2(SiO4)3 |
| Fe | Iron | |
| Fe | ⓘ Chromite | Fe2+Cr23+O4 |
Other Databases
| Link to USGS MRDS: | 10098573 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
- Coast MountainsMountain Range
North America PlateTectonic Plate
- California Coast RangesAccretionary Complex
- Franciscan DomainDomain
USA
- California
- Diablo RangeMountain Range
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Mendenhall No. 1 Mine, Cedar Mountain, Cedar Mountain Mining District, Alameda County, California, USA