Golden Gate group (Golden Gate Gp; Kentucky & Alpha; Golden Gate; Golden Gate East and West; Dana claim; Christopher Columbus claim; Golden Gate claim; Alpha claim; Ismert Ranch claim), Grass Valley, Grass Valley Mining District, Nevada County, California, USAi
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
39° 13' 31'' North , 121° 2' 15'' West
Latitude & Longitude (decimal):
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Grass Valley | 12,944 (2017) | 2.1km |
| Nevada City | 3,152 (2017) | 4.4km |
| Rough and Ready | 963 (2011) | 8.5km |
| Alta Sierra | 6,911 (2011) | 9.4km |
| Penn Valley | 1,621 (2011) | 13.6km |
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 |
|---|---|---|
| Nevada County Gem & Mineral Society | Grass Valley, California | 2km |
| Sutter Buttes Gem & Mineral Society | Marysville, California | 49km |
A former lode Au-Cr occurrence/mine group located in the NW¼ sec. 25 & in sec. 26, T16N, R8E, MDM, ¾ mile NE of Grass Valley. Property comprises 200 acres. MRDS database stated accuracy for this location is 500 meters.
Mineralization is hosted in serpentinite and diabase. The ore body is lenticular in form, strikes E and dips 30-34N at a thickness of 1.52 meters. There are 5 veins, the Golden Gate vein, Dana-Mobile Treasury vein, Alpha vein, Blight and Wills veins. The veins average 18 inches (45 cm) thick. Diabase dikes occur in serpentine. Altered serpentine contains mariposite. Local rocks include Mesozoic volcanic rocks, unit 2 (Western Sierra Foothills and Western Klamath Mountains).
Workings include underground openings with a length of 1,645.92 meters and an overall depth of 151.79 meters and are comprised of a 1,020 foot incline, 3,315 feet of drifts, 485 feet of crosscuts, 420 feet of raises.
Analytical data results: The pyrite assayed at $150 (period values) Au/ton.
Production data are found in: Logan, Clarence August (1941).
production information: Concentrate less than 1% of ore and averaged $45 to $50 (period values) Au/ton. A small carload of chrome ore was mined.
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsMineral List
Mineral list contains entries from the region specified including sub-localities4 valid minerals.
Detailed Mineral List:
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
| Group 9 - Silicates | |||
| ⓘ | Muscovite | 9.EC.15 | KAl2(AlSi3O10)(OH)2 |
| ⓘ | var. Phengite | 9.EC.15 | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| ⓘ | var. Mariposite | 9.EC.15 | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| Unclassified | |||
| ⓘ | 'Serpentine Subgroup' | - | D3[Si2O5](OH)4 |
List of minerals for each chemical element
| H | Hydrogen | |
|---|---|---|
| H | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| H | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| H | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| H | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| O | Oxygen | |
| O | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| O | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| O | ⓘ Quartz | SiO2 |
| O | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| O | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| Mg | Magnesium | |
| Mg | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| Al | Aluminium | |
| Al | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| Al | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| Al | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| Si | Silicon | |
| Si | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| Si | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| Si | ⓘ Quartz | SiO2 |
| Si | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| Si | ⓘ Serpentine Subgroup | D3[Si2O5](OH)4 |
| S | Sulfur | |
| S | ⓘ Pyrite | FeS2 |
| K | Potassium | |
| K | ⓘ Muscovite | KAl2(AlSi3O10)(OH)2 |
| K | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| K | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| Cr | Chromium | |
| Cr | ⓘ Muscovite var. Mariposite | K(Al,Cr)2(Al,Si)4O10(OH)2 |
| Fe | Iron | |
| Fe | ⓘ Muscovite var. Phengite | KAl1.5(Mg,Fe)0.5(Al0.5Si3.5O10)(OH)2 |
| Fe | ⓘ Pyrite | FeS2 |
| Au | Gold | |
| Au | ⓘ Gold | Au |
Other Databases
| Link to USGS MRDS: | 10101250 |
|---|
Localities in this Region
- California
- Nevada County
- Grass Valley Mining District
- Grass Valley
- Golden Gate group (Golden Gate Gp; Kentucky & Alpha; Golden Gate; Golden Gate East and West; Dana claim; Christopher Columbus claim; Golden Gate claim; Alpha claim; Ismert Ranch claim)
- Grass Valley
- Grass Valley Mining District
- Nevada County
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Foothills-Wallowa DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- Sierra NevadaMountain Range
This page contains all mineral locality references listed on mindat.org. 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 mindat.org 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.
References
(n.d.) Minerals Availability System (MAS), U.S. Bureau of Mines.file #0060570348
