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
Dicker Willem (Dicker Wilhelm; Garubberg), ǃNamiǂNûs Constituency, ǁKaras Region, Namibia


Locality type:Intrusion
Classification
Species:'Biotite' (not an IMA approved species)
Formula:K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Age information
Maximum recorded age:49.8 ± 0.8 Ma
Minimum recorded age:48 ± 2 Ma
Sample ages:
Recorded ageGeologic TimeSampleDating method
148 ± 2 MaEocene - K-Ar
249.8 ± 0.8 MaEocene - Rb-Sr
Sample references:
1 -
Reid, D. L., Cooper, A. F., Rex, D. C., Harmer, R. E. (1990) Timing of post–Karoo alkaline volcanism in southern Namibia. Geological Magazine, 127 (5) 427-433 doi:10.1017/s001675680001517x
2 -
Reid, D. L., Cooper, A. F., Rex, D. C., Harmer, R. E. (1990) Timing of post–Karoo alkaline volcanism in southern Namibia. Geological Magazine, 127 (5) 427-433 doi:10.1017/s001675680001517x
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view Dicker Willem (Dicker Wilhelm; Garubberg), ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
Data Identifiers
Mindat Occurrence Record ID:260302
Long-form Identifier:1:3:260302:5
GUID (UUID V4):0
Nearest other occurrences of Biotite
18.6km (11.5 miles) ⓘKeishohe carbonatites, ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
21.0km (13.1 miles) ⓘKieshöhe carbonatite, ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
48.5km (30.2 miles) ⓘTefelskuppe Hills, ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
92.2km (57.3 miles) ⓘDrachenberg Complex, ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
94.2km (58.5 miles) ⓘGranitberg Complex, ǃNamiǂNûs Constituency, ǁKaras Region, Namibia
References
 
and/or  
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