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
Fontao mines, Silleda, Pontevedra, Galicia, Spain


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 Fontao mines, Silleda, Pontevedra, Galicia, Spain
Data Identifiers
Mindat Occurrence Record ID:1651407
Long-form Identifier:1:3:1651407:2
GUID (UUID V4):0
Nearest other occurrences of Biotite
6.9km (4.3 miles) ⓘForcarei Norte pegmatite field, Silleda, Pontevedra, Galicia, Spain
26.2km (16.3 miles) ⓘPanceiros pegmatite, Campo Lameiro, Pontevedra, Galicia, Spain
34.1km (21.2 miles) ⓘTouro Copper Project, Touro, A Coruña, Galicia, Spain
34.1km (21.2 miles) ⓘArienteiro deposit, Touro Copper Project, Touro, A Coruña, Galicia, Spain
47.4km (29.4 miles) ⓘA Franqueira, A Cañiza, Pontevedra, Galicia, Spain
52.8km (32.8 miles) ⓘCillarga Quarry, Ponteareas, Pontevedra, Galicia, Spain
55.7km (34.6 miles) ⓘSan Finx Mines, Vilacova, Lousame, A Coruña, Galicia, Spain
56.7km (35.2 miles) ⓘMount Ermelo, Moaña, Pontevedra, Galicia, Spain
56.9km (35.3 miles) ⓘPorriño quarries, Porriño, Pontevedra, Galicia, Spain
61.9km (38.5 miles) ⓘImpensada Mine (Magnesitas de Rubián), Pacios, Vila de Mouros, Incio, Lugo, Galicia, Spain
References
Borrajo, Iñigo; Tornos, Fernando; Stein, Holly; Hanchar, John M. (2024) Geochronology and decoupling controls of Sn-(Ta-Li) and W-(Sn) mineralization in the Iberian Variscan Massif, Spain and Portugal. Ore Geology Reviews, 173. 106253 doi:10.1016/j.oregeorev.2024.106253
Losantos, Emma; Borrajo, Iñigo; Losada, Iván; Boixet, Lluís; Castelo Branco, José M.; Tornos, Fernando (2025) Sn and W mineralisation in the Iberian Peninsula. Ore Geology Reviews, 179. 106542 doi:10.1016/j.oregeorev.2025.106542
 
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