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
State Route 9 rock cuts, Haddam, Middlesex County, Connecticut, USA


Classification
Species:'Biotite' (not an IMA approved species)
Formula:K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2
Habit:anhedral
Colour:black
Quality for species:Rock forming mineral/non-crystalline/little interest for collectors.(##)
Abundance at site:Very common
Confirmation
Validity:Confirmed
Confirmation Methods:Visually Identified
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view State Route 9 rock cuts, Haddam, Middlesex County, Connecticut, USA
Data Identifiers
Mindat Occurrence Record ID:920658
Long-form Identifier:1:3:920658:8
GUID (UUID V4):0
Nearest other occurrences of Biotite
1.3km (0.8 miles) ⓘState Route 9 Interchange 13 - Beaver Meadow Road, Haddam, Middlesex County, Connecticut, USA
2.7km (1.7 miles) ⓘTimms Hill (Tim's Hill; Iolite Hill), Haddam, Middlesex County, Connecticut, USA
2.9km (1.8 miles) ⓘJail Hill Road locality (Jail Hill Quarry), Haddam, Middlesex County, Connecticut, USA
3.1km (1.9 miles) ⓘArnold Granite Quarry (General Brainerd Quarry; Great Hill Quarry; Hazelton Quarry; Haddam Quarry; Brookes Quarry), Haddam, Middlesex County, Connecticut, USA
7.8km (4.9 miles) ⓘBailey prospect, East Hampton, Middlesex County, Connecticut, USA
8.9km (5.5 miles) ⓘJohn Salak Quarry, Haddam, Middlesex County, Connecticut, USA
9.3km (5.8 miles) ⓘWorth and Selden Quarries (Victoria Quarry), East Hampton, Middlesex County, Connecticut, USA
10.7km (6.7 miles) ⓘHaynes Deep River Quarry, Deep River, Middlesex County, Connecticut, USA
12.9km (8.0 miles) ⓘRockland Preserve, Madison, New Haven County, Connecticut, USA
14.4km (8.9 miles) ⓘLyman Viaduct at Dickinson Creek, Westchester, Colchester, New London County, Connecticut, USA
References
Lundgren, Lawrence Jr. (1979) The Bedrock Geology of the Haddam Quadrangle. Quadrangle Report 37.. State Geological and Natural History Survey of Connecticutp.37
 
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