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 Pedro das Águias Mine, U.F Távora e Pereiro, Tabuaço, Viseu, 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:Believed Valid
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view São Pedro das Águias Mine, U.F Távora e Pereiro, Tabuaço, Viseu, Portugal
Data Identifiers
Mindat Occurrence Record ID:1664944
Long-form Identifier:1:3:1664944:8
GUID (UUID V4):0
Nearest other occurrences of Biotite
20.9km (13.0 miles) ⓘAlijó spodumene pegmatite, São Mamede de Ribatua, Alijó, Vila Real, Portugal
25.9km (16.1 miles) ⓘRatoeira No. 1 quarry, U.F. Sequeiros e Gradiz, Aguiar da Beira, Guarda, Portugal
26.4km (16.4 miles) ⓘRatoeira quarry, U.F. Sequeiros e Gradiz, Aguiar da Beira, Guarda, Portugal
28.5km (17.7 miles) ⓘNumão prospect, Numão, Vila Nova de Foz Côa, Guarda, Portugal
29.8km (18.5 miles) ⓘVigia Mine, U.F. Aguiar da Beira e Coruche, Aguiar da Beira, Guarda, Portugal
30.7km (19.1 miles) ⓘAssunção Mine, Aldeia Nova, Ferreira de Aves, Sátão, Viseu, Portugal
36.4km (22.6 miles) ⓘFonte Limeira quarry, U.F Romãs Decermilo e Vila Longa, Sátão, Viseu, Portugal
37.5km (23.3 miles) ⓘLamas de Olo pluton, Vila Marim, Vila Real, Vila Real, Portugal
42.8km (26.6 miles) ⓘVenturinha, Sezures, Penalva do Castelo, Viseu, Portugal
49.2km (30.6 miles) ⓘMonte de Entre-Portelas Mine (S. João Mine; Adoria Mine), Cerva e Limões, Ribeira de Pena, Vila Real, Portugal
References
Ramos, Violeta, Noronha, Fernando, Seltmann, Reimar, Dolgopolova, Alla, Guedes, Alexandra, Andersen, Jens, Spruženiece, Liene, Simons, Beth, Rollinson, Gavyn, Pickles, Joe, et al. (2024) São Pedro das Águias skarn: A W-(Sn) deposit from the Douro Scheelite Belt, Northern Portugal. Ore Geology Reviews, 175. 106348 doi:10.1016/j.oregeorev.2024.106348
 
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