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
Ellicott City, Howard County, Maryland, USA


00318260017369614315672.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
05255310017369614319449.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
05682920017272071721203.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
05255310017369614319449.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
05682920017272071721203.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
05255310017369614319449.jpg
Biotite, etc.

Ellicott City, Howard County, Maryland, USA
Locality type:Census-designated Place
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
Associated Minerals Based on Photo Data:
Calcite2
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view Ellicott City, Howard County, Maryland, USA
Data Identifiers
Mindat Occurrence Record ID:202151
Long-form Identifier:1:3:202151:5
GUID (UUID V4):0
Localities for Biotite in this Region
Weber's Quarry, Ellicott City, Howard County, Maryland, USA
Nearest other occurrences of Biotite
0.2km (0.1 miles) ⓘWeber's Quarry, Ellicott City, Howard County, Maryland, USA
0.7km (0.4 miles) ⓘGaither's Quarry, Baltimore County, Maryland, USA
7.3km (4.5 miles) ⓘFrost Quarry, Davis, Howard County, Maryland, USA
11.5km (7.1 miles) ⓘHilton Quarry, Baltimore City, Maryland, USA
13.3km (8.3 miles) ⓘMarriottsville Quarry, Hernwood, Baltimore County, Maryland, USA
15.8km (9.8 miles) ⓘMcMahon Quarry (Greenspring Quarry), Pikesville, Baltimore County, Maryland, USA
15.8km (9.8 miles) ⓘJones Falls Quarries, Baltimore City, Maryland, USA
16.5km (10.3 miles) ⓘWright Quarry, Stony Run, Baltimore City, Maryland, USA
16.7km (10.4 miles) ⓘStony Run, Baltimore City, Maryland, USA
18.0km (11.2 miles) ⓘBrighton Dam Road Quarry (Howard-Montgomery Quarry), Howard County, Maryland, USA
References
Bernstein, Lawrence R. (1980) Minerals of the Washington, D.C. Area - Issue 5 of Educational series, Maryland Geological Survey. Department of Natural Resources, Maryland Geological Survey. p.1-148.
 
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