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
Jones Falls Quarries, Baltimore City, 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
Comments:Occurs in gneiss.
Confirmation
Validity:Believed Valid
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view Jones Falls Quarries, Baltimore City, Maryland, USA
Data Identifiers
Mindat Occurrence Record ID:70525
Long-form Identifier:1:3:70525:7
GUID (UUID V4):0
Nearest other occurrences of Biotite
1.5km (0.9 miles) ⓘWright Quarry, Stony Run, Baltimore City, Maryland, USA
1.8km (1.1 miles) ⓘStony Run, Baltimore City, Maryland, USA
5.2km (3.2 miles) ⓘHilton Quarry, Baltimore City, Maryland, USA
9.2km (5.7 miles) ⓘMcMahon Quarry (Greenspring Quarry), Pikesville, Baltimore County, Maryland, USA
9.3km (5.7 miles) ⓘStaurolite locality, Rockland, Baltimore County, Maryland, USA
13.9km (8.6 miles) ⓘMarble/pegmatite quarry, Loch Raven, Carney, Baltimore County, Maryland, USA
15.3km (9.5 miles) ⓘGaither's Quarry, Baltimore County, Maryland, USA
15.5km (9.6 miles) ⓘArundel Quarry, Baltimore County, Maryland, USA
15.8km (9.8 miles) ⓘEllicott City, Howard County, Maryland, USA
16.0km (9.9 miles) ⓘWeber's Quarry, Ellicott City, Howard County, Maryland, USA
References
Dana 6:1070
Rocks & Min.:10:110.
Ostrander, Charles W., Price, Jr, Walter E. (1940) Minerals of Maryland. The Natural History Society of Maryland, Baltimore, Maryland, USA. 14pp.
 
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