Red Rock Island deposit, Richmond, Contra Costa County, California, USAi
| Regional Level Types | |
|---|---|
| Red Rock Island deposit | Deposit |
| Richmond | City |
| Contra Costa County | County |
| California | State |
| USA | Country |
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Latitude & Longitude (WGS84):
37° 55' 45'' North , 122° 25' 46'' West
Latitude & Longitude (decimal):
Type:
Köppen climate type:
Nearest Settlements:
| Place | Population | Distance |
|---|---|---|
| North Richmond | 3,717 (2011) | 6.4km |
| Tiburon | 9,214 (2018) | 6.6km |
| Belvedere | 2,121 (2018) | 7.0km |
| Richmond | 109,708 (2017) | 7.2km |
| Strawberry | 5,393 (2011) | 7.8km |
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 |
|---|---|---|
| San Francisco Gem and Mineral Society, Inc. | San Francisco, California | 17km |
| Northern California Geological Society | Orinda, California | 23km |
| Vallejo Gem & Mineral Society | Vallejo, California | 25km |
| Contra Costa Mineral & Gem Society | Concord, California | 35km |
| East Bay Mineral and Lapidary Club | Hayward, California | 41km |
A Mn-mineral paint occurrence/mine located in the N½ sec. 16, T1N, R5W, MDM, on the SW side of Red Rock Island, an island in San Francisco Bay, off the coast of Richmond, and 7.3 km (4.5 miles) W of Richmond center. Discovered in 1914. MRDS database stated accuracy for this location is 500 meters.
Mineralization is hosted in Late Cretaceous shale and Franciscan Complex chert. The ore body strikes WNW and dips vertically at a thickness of 0.01 meter (this represents the thickness of an individual ore layer as described. The thickness of the ore zone is not stated). Interstratified layers of psilomelane (mostly ¼ to ½ inch [0.62 to 1.25 cm] thick in radiolarin chert of the Franciscan complex. Shale partings are locally replaced by psilomelane. The ore appears to be primary, contemporaneous with deposition of silica that formed the cherts. Associated red chert was once mined as mineral paint.
Workings include unspecified surface openings.
Production in 1867 of possible 200 tons of ore from this deposit has been reported.
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
1 valid mineral.
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:
| ⓘ 'Psilomelane' References: |
| ⓘ Pyrolusite Formula: Mn4+O2 |
Gallery:
List of minerals arranged by Strunz 10th Edition classification
| Group 4 - Oxides and Hydroxides | |||
|---|---|---|---|
| ⓘ | Pyrolusite | 4.DB.05 | Mn4+O2 |
| Unclassified | |||
| ⓘ | 'Psilomelane' | - | |
List of minerals for each chemical element
| O | Oxygen | |
|---|---|---|
| O | ⓘ Pyrolusite | Mn4+O2 |
| Mn | Manganese | |
| Mn | ⓘ Pyrolusite | Mn4+O2 |
Other Databases
| Link to USGS MRDS: | 10029596 |
|---|
Other Regions, Features and Areas containing this locality
North AmericaContinent
North America PlateTectonic Plate
- California Coast RangesAccretionary Complex
- Franciscan DomainDomain
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