Vote for your favorite mineral in #MinCup26! - Quartz vs. Asagiite
It's a classic vs a newbie as the most common named mineral in the crust Quartz is up against an exceedingly-rare sea foam-green mineral discovered just a few years ago Asagiite.
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

Biotite from
D. João quarry (Herdade do Padre João), Monforte, Monforte, Portalegre, Portugal


Locality type:Quarry
Classification
Species:'Biotite' (not an IMA approved species)
Formula:K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view D. João quarry (Herdade do Padre João), Monforte, Monforte, Portalegre, Portugal
Data Identifiers
Mindat Occurrence Record ID:828396
Long-form Identifier:1:3:828396:2
GUID (UUID V4):0
Nearest other occurrences of Biotite
15.4km (9.5 miles) ⓘCabeço de Vide ultramafic complex, Alter do Chão, Portalegre, Portugal
34.1km (21.2 miles) ⓘCevadais occurrence, Campo Maior, Portalegre, Portugal
76.6km (47.6 miles) ⓘBarrocal quarries, Nossa Senhora da Tourega e Nossa Senhora de Guadalupe, Évora, Évora, Portugal
76.9km (47.8 miles) ⓘSierra de San Pedro, Cáceres, Cáceres, Extremadura, Spain
78.7km (48.9 miles) ⓘPedras Pintas Mine, Cortiçadas de Lavre e Lavre, Montemor-o-Novo, Évora, Portugal
83.9km (52.1 miles) ⓘCasas Novas Mine, Santiago do Escoural, Montemor-o-Novo, Évora, Portugal
91.7km (57.0 miles) ⓘSegura Mines (Segura mining field), União das Freguesias de Zebreira e Segura, Idanha-a-Nova, Castelo Branco, Portugal
92.3km (57.4 miles) ⓘCerro Queimado, União das Freguesias de Zebreira e Segura, Idanha-a-Nova, Castelo Branco, Portugal
93.3km (58.0 miles) ⓘMonfurado gold prospect, São Cristóvão, Montemor-o-Novo, Évora, Portugal
References
LNEG - Siorminp database information
 
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 6, 2026 10:49:07
Go to top of page