Vote for your favorite mineral in #MinCup26! - Cuprite vs. Orpiment
It's a fiery match of vibrant red Cuprite and just as saturated orange Orpiment battle for your votes!
Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic TimeExplore Fossils
Minerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral QuizTime Machine
Photo SearchPhoto GalleriesSearch by ColorPhoto Colour ExplorerNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Star Mine, Contra Costa County, California, USAi
Regional Level Types
Star MineMine (Abandoned)
Contra Costa CountyCounty
CaliforniaState
USACountry

This page is currently not sponsored. Click here to sponsor this page.
PhotosMapsSearch
Latitude & Longitude (WGS84):
37° 56' 40'' North , 121° 49' 29'' West
Latitude & Longitude (decimal):
37.94452,-121.82495
GeoHash:
G#: 9q9rgg9fc
GRN:
N26W69
Type:
Mine (Abandoned) - last checked 2024
Köppen climate type:
Csb : Warm-summer Mediterranean climate
Nearest Settlements:
PlacePopulationDistance
Antioch110,542 (2017)6.9km
Clayton11,867 (2017)9.7km
Pittsburg69,424 (2017)10.6km
Brentwood58,968 (2017)11.4km
Oakley39,813 (2017)11.5km
Nearest Clubs:
Local clubs are the best way to get access to collecting localities
ClubLocationDistance
Antioch Lapidary ClubAntioch, California7km
Contra Costa Mineral & Gem SocietyConcord, California18km
Livermore Valley LithophilesLivermore, California30km
Northern California Geological SocietyOrinda, California32km
Mineral & Gem Society of Castro ValleyHayward, California38km
Mindat Locality ID:
442187
Long-form identifier:
mindat:1:2:442187:3
GUID (UUID V4):
0


An inactive coal mine (though it was one of the last active coal mines in the area) located within the Black Diamond Mines Regional Preserve. The entrance tunnel, now barred, can be seen up close from one of the trails in the preserve. A star symbol at the top center of the entrance identifies this mine.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded at this locality.


List of minerals for each chemical element

Other Regions, Features and Areas containing this locality

North AmericaContinent
North America PlateTectonic Plate
USA

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.
Quick NavTopCommoditiesOther Regions
 
and/or  
Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 5, 2026 07:41:07 Page updated: August 8, 2025 19:25:31
Go to top of page