Keystone Mine (Keystone group; Keystone claim; Spring Hill claim; Geneva claim; Granite State claim; Niagara claim; East Keystone claim), Amador City, Jackson-Plymouth Mining District, Amador County, California, USAi
This page is currently not sponsored. Click here to sponsor this page.
Latitude & Longitude (WGS84):
38° 25' 5'' North , 120° 49' 18'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| Amador City | 189 (2017) | 0.3km |
| Sutter Creek | 2,488 (2017) | 3.3km |
| Drytown | 167 (2011) | 3.8km |
| Martell | 282 (2011) | 6.1km |
| Plymouth | 960 (2017) | 7.4km |
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 |
|---|---|---|
| Amador County Gem & Mineral Society | Sutter Creek, California | 3km |
| El Dorado County Mineral and Gem Society | Placerville, California | 35km |
| Gold Country Treasure Seekers | Placerville, California | 35km |
| Calaveras Gem & Mineral Society | Angels Camp, California | 46km |
A former lode Au-As-Sb mine located in sec. 36, T7N, R10E, MDM, 0.2 km (0.1 mile) SE of Amador City proper (within the city limits; adjoins the South Spring Hill Mine to the E), on private land. Discovered in 1851. Operated by the Keystone Mining Co., C/O John D. Culbert. Operated during the periods 1851 to 1919 and reopened 1933 to 1942 under government order. MRDS database stated accuracy for this location is 100 meters.
The mine was formed of several claims located in 1851 and was one of the most profitable in the Mother Lode, producing $24,000,000 (period values) during operations. Worked until 1919 and reopened in 1933 and produced 1935-1942. It has been idle since except for a small amount of work done in 1952. Much high-grade ore was produced until 1888. During operations in the period 1935 to 1942, it produced about $1,000,000 (period values). Production was from the 900 to 2,100 foot levels, mostly from the 1,400 to 2,100 levels.
Mineralization is hosted in slate and greenstone. The ore body is 60.96 meters thick. The MAin vein (or Contact vein) varies in thickness from 12 to 200 feet between a slate footwall and a greenstone hanging wall. The vein dips from 35 to 65 degrees E. The ore occurs in veins and quartz stringers branching from the vein. The gold is both free and associated with sulfides. Local rocks include Jurassic marine rocks, unit 1 (Western Sierra Nevada and Western Klamath Mountains).
Workings include underground openings. The main shaft is 2,680 feet of a 52 degree incline with production on the 900 to 2,100 foot levels, with extensive crosscutting.
In the fiscal year ending 7/31/1867 approximately 12,000 tons of ore were mined. The average yield per ton was $12.86 (period values).
Select Mineral List Type
Standard Detailed Gallery Strunz Chemical ElementsDetailed Mineral List:
| ⓘ Chalcopyrite Formula: CuFeS2 |
| ⓘ Galena Formula: PbS |
| ⓘ Native Gold Formula: Au |
| ⓘ Pyrite Formula: FeS2 |
| ⓘ Quartz Formula: SiO2 |
| ⓘ Stibnite Formula: Sb2S3 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 1 - Elements | |||
|---|---|---|---|
| ⓘ | Native Gold | 1.AA.05 | Au |
| Group 2 - Sulphides and Sulfosalts | |||
| ⓘ | Chalcopyrite | 2.CB.10a | CuFeS2 |
| ⓘ | Galena | 2.CD.10 | PbS |
| ⓘ | Stibnite | 2.DB.05 | Sb2S3 |
| ⓘ | Pyrite | 2.EB.05a | FeS2 |
| Group 4 - Oxides and Hydroxides | |||
| ⓘ | Quartz | 4.DA.05 | SiO2 |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Quartz | SiO2 |
| Si | Silicon | |
| Si | ⓘ Quartz | SiO2 |
| S | Sulfur | |
| S | ⓘ Chalcopyrite | CuFeS2 |
| S | ⓘ Galena | PbS |
| S | ⓘ Pyrite | FeS2 |
| S | ⓘ Stibnite | Sb2S3 |
| Fe | Iron | |
| Fe | ⓘ Chalcopyrite | CuFeS2 |
| Fe | ⓘ Pyrite | FeS2 |
| Cu | Copper | |
| Cu | ⓘ Chalcopyrite | CuFeS2 |
| Sb | Antimony | |
| Sb | ⓘ Stibnite | Sb2S3 |
| Au | Gold | |
| Au | ⓘ Native Gold | Au |
| Pb | Lead | |
| Pb | ⓘ Galena | PbS |
Other Databases
| Link to USGS MRDS: | 10028175 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- Calaveras-Baker DomainDomain
- Sierra Nevada BatholithVolcanic Arc
USA
- California
- Amador County
- Mother Lode BeltBelt
- Mother Lode BeltBelt
- Amador County
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.
Keystone Mine, Amador City, Jackson-Plymouth Mining District, Amador County, California, USA