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 Time
Minerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
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
╳Discussions
💬 Home🔎 Search🚩 Flagged📅 LatestGroups
EducationOpen discussion area.Fakes & FraudsOpen discussion area.Field CollectingOpen discussion area.FossilsOpen discussion area.Gems and GemologyOpen discussion area.GeneralOpen discussion area.How to ContributeOpen discussion area.Identity HelpOpen discussion area.Improving Mindat.orgOpen discussion area.LocalitiesOpen discussion area.Lost and Stolen SpecimensOpen discussion area.MeteoritesOpen discussion area.Mindat SalesOpen discussion area.Mineral ExchangesOpen discussion area.Mineral PhotographyOpen discussion area.Mineral ShowsOpen discussion area.Mineralogical ClassificationOpen discussion area.Mineralogy CourseOpen discussion area.MineralsOpen discussion area.Minerals and MuseumsOpen discussion area.PhotosOpen discussion area.Techniques for CollectorsOpen discussion area.The Rock H. Currier Digital LibraryOpen discussion area.UV MineralsOpen discussion area.Recent Images in Discussions
25077
LocalitiesMn occurrence, East Foothills, Black Wonder Mining District, Santa Clara County, California, USA
22nd May 2026 14:48 UTCJeff Weissman Expert OP
This has been bothering me for a long time. There is no "San Jose Mine". The locality was an erratic boulder sitting in the valley of the Penitencia Creek in Alum Rock Park, a part of the city of San Jose, California. There was never a mine, although the bolder, rich in manganese minerals, was indeed hauled away and processed for its Mn content, over 100 years ago. No reference on this occurrence mentions anything about a "mine." References are given on the locality page, for review if desired.
The proper locality name should be "manganese occurrence in Penitencia Creek, Alum Rock Park, San Jose, Santa Clara County, California, USA" or similar. This will then align the locality with all of the references to the minerals that were found in the now absent Mn-rich bolder. And certainly, this is not part of the "Black Wonder Mining Distict", since no mining took place.
Thoughts/comments?
22nd May 2026 15:36 UTCTony Nikischer 🌟 Manager
From what I can see in the lliterature, you are correct. Similar problems exist in several Virginia localities where names were "given" by collectors to local collecting spots that were never formally named as such (a review is underway on that front).
22nd May 2026 19:03 UTCGiles Peatfield
If the boulder is "now absent", perhaps the locality name should reflect that point? Historic manganese occurrence? Pre-existing manganese occurrence? Or something else? This just to point out clearly that there is no use going to look for it at this late stage. Thoughts?
Cheers, Giles
25th May 2026 17:49 UTCUwe Kolitsch Manager
Mn occurrence would seem right.
25th May 2026 18:07 UTCGiles Peatfield
Agreed, Uwe.
After I made this comment, I remembered preparing a posting (Skagit Bluffs axinite occurrence) at which the actual mineral occurrence had presumably been destroyed during highway upgrading - so it was "former" - much the same as this case. So "Mn occurrence" would indeed seem appropriate.
Best, Giles
25th May 2026 20:17 UTCUwe Kolitsch Manager
Ok, fixed.
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.
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: May 26, 2026 04:06:39
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.
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: May 26, 2026 04:06:39