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.
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Biotite from
São Miguel de Acha Mines, São Miguel de Acha, Idanha-a-Nova, Castelo Branco, Portugal


Locality type:Mine
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:Confirmed
Confirmation Methods:Visually Identified
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view São Miguel de Acha Mines, São Miguel de Acha, Idanha-a-Nova, Castelo Branco, Portugal
Data Identifiers
Mindat Occurrence Record ID:855287
Long-form Identifier:1:3:855287:7
GUID (UUID V4):0
Nearest other occurrences of Biotite
17.8km (11.1 miles) ⓘGranite outcrop, União de Freguesias de Monsanto e Idanha-a-Velha, Idanha-a-Nova, Castelo Branco, Portugal
36.0km (22.4 miles) ⓘSegura Mines (Segura mining field), União das Freguesias de Zebreira e Segura, Idanha-a-Nova, Castelo Branco, Portugal
37.0km (23.0 miles) ⓘCerro Queimado, União das Freguesias de Zebreira e Segura, Idanha-a-Nova, Castelo Branco, Portugal
73.1km (45.4 miles) ⓘVila Seca Mine, Vila Seca, Tavares (Chãs; Várzea e Travanca), Mangualde, Viseu, Portugal
73.2km (45.5 miles) ⓘRochel, Cubos-Mesquitela-Mangualde area, Mangualde (Mesquitela e Cunha Alta), Mangualde, Viseu, Portugal
73.3km (45.5 miles) ⓘChão do Castanheiro, Cubos-Mesquitela-Mangualde area, Mangualde (Mesquitela e Cunha Alta), Mangualde, Viseu, Portugal
73.9km (45.9 miles) ⓘCubos-Mesquitela-Mangualde area, Mangualde (Mesquitela e Cunha Alta), Mangualde, Viseu, Portugal
77.1km (47.9 miles) ⓘPicoto Mine, Vilar Seco, Nelas, Viseu, Portugal
77.6km (48.2 miles) ⓘRegada, Cubos-Mesquitela-Mangualde area, Mangualde (Mesquitela e Cunha Alta), Mangualde, Viseu, Portugal
82.6km (51.3 miles) ⓘVenturinha, Sezures, Penalva do Castelo, Viseu, Portugal
References
Nunes, Rui (n.d.) Personal communication.
 
and/or  
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