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It's a showdown with rare earth elemental ore Monazite-(Ce) and index mineral Andalusite.
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Biotite from
Cape Roca, Colares, Sintra, Lisbon, Portugal


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 Cape Roca, Colares, Sintra, Lisbon, Portugal
Data Identifiers
Mindat Occurrence Record ID:1412261
Long-form Identifier:1:3:1412261:9
GUID (UUID V4):0
Nearest other occurrences of Biotite
4.0km (2.5 miles) ⓘBiscaia quarry, Biscaia, Alcabideche, Cascais, Lisbon, Portugal
70.6km (43.8 miles) ⓘBerlengas Islands, Peniche, Leiria, Portugal
98.2km (61.0 miles) ⓘMonte de São Bartolomeu, Nazaré, Nazaré, Leiria, Portugal
References
Ramalho, M. M. et al. (1993) - Carta geológica de Portugal, folha 34-A, Sintra. Direcção-geral de Geologia e Minas, Serviços Geológicos de Portugal. Lisboa.
 
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