Vote for your favorite mineral in #MinCup26! - Sphalerite vs. Anorthite
Both zinc ore Sphalerite and calcium plagioclase feldspar Anorthite have perfect cleavage that will split cleanly if you hit them with a hammer, but only one can claim a larger split of your votes!
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Biotite from
Frost Quarry, Davis, Howard County, Maryland, USA


Locality type:Quarry
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 Frost Quarry, Davis, Howard County, Maryland, USA
Data Identifiers
Mindat Occurrence Record ID:202016
Long-form Identifier:1:3:202016:7
GUID (UUID V4):0
Nearest other occurrences of Biotite
6.8km (4.2 miles) ⓘMarriottsville Quarry, Hernwood, Baltimore County, Maryland, USA
7.2km (4.5 miles) ⓘWeber's Quarry, Ellicott City, Howard County, Maryland, USA
7.3km (4.5 miles) ⓘEllicott City, Howard County, Maryland, USA
7.9km (4.9 miles) ⓘGaither's Quarry, Baltimore County, Maryland, USA
15.2km (9.5 miles) ⓘMineral Hill Mine, Louisville, Carroll County, Maryland, USA
16.2km (10.1 miles) ⓘMcMahon Quarry (Greenspring Quarry), Pikesville, Baltimore County, Maryland, USA
16.8km (10.4 miles) ⓘHilton Quarry, Baltimore City, Maryland, USA
17.2km (10.7 miles) ⓘBrighton Dam Road Quarry (Howard-Montgomery Quarry), Howard County, Maryland, USA
19.1km (11.9 miles) ⓘStaurolite locality, Rockland, Baltimore County, Maryland, USA
19.6km (12.2 miles) ⓘPatapsco Mine (Finksburg Mine; Orchard Mine), Patapsco Mines, Finksburg, Carroll County, Maryland, USA
References
Mines of the Washington D.C Area
 
and/or  
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