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
Jail Hill Road locality (Jail Hill Quarry), Haddam, Middlesex County, Connecticut, USA


05322680017272040458893.jpg
Biotite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
01709020017368272416990.jpg
Biotite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
05322680017272040458893.jpg
Biotite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
01709020017368272416990.jpg
Biotite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
05322680017272040458893.jpg
Biotite, etc.

Jail Hill Road locality, Haddam, Middlesex County, Connecticut, USA
01709020017368272416990.jpg
Biotite, etc.

Jail Hill Road locality, 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
Comments:Mostly in the schist surrounding the pegmatite and Mn-rich pod, though some biotite is mixed with spessartine along the latter's contact.
Habit:subhedral tabular
Colour:black
Quality for species:Rock forming mineral/non-crystalline/little interest for collectors.(##)
Abundance at site:Common
Confirmation
Validity:Confirmed
Confirmation Methods:Visually Identified
Associated Minerals Based on Photo Data:
Spessartine4
Fluorapatite1
Data
Mineral Data:Click here to view Biotite data
Locality Data:Click here to view Jail Hill Road locality (Jail Hill Quarry), Haddam, Middlesex County, Connecticut, USA
Data Identifiers
Mindat Occurrence Record ID:706207
Long-form Identifier:1:3:706207:0
GUID (UUID V4):0
Nearest other occurrences of Biotite
0.4km (0.3 miles) ⓘArnold Granite Quarry (General Brainerd Quarry; Great Hill Quarry; Hazelton Quarry; Haddam Quarry; Brookes Quarry), Haddam, Middlesex County, Connecticut, USA
1.0km (0.6 miles) ⓘTimms Hill (Tim's Hill; Iolite Hill), Haddam, Middlesex County, Connecticut, USA
2.1km (1.3 miles) ⓘState Route 9 Interchange 13 - Beaver Meadow Road, Haddam, Middlesex County, Connecticut, USA
2.9km (1.8 miles) ⓘState Route 9 rock cuts, Haddam, Middlesex County, Connecticut, USA
5.1km (3.1 miles) ⓘBailey prospect, East Hampton, Middlesex County, Connecticut, USA
6.7km (4.1 miles) ⓘWorth and Selden Quarries (Victoria Quarry), East Hampton, Middlesex County, Connecticut, USA
8.5km (5.3 miles) ⓘJohn Salak Quarry, Haddam, Middlesex County, Connecticut, USA
11.5km (7.2 miles) ⓘLyman Viaduct at Dickinson Creek, Westchester, Colchester, New London County, Connecticut, USA
11.9km (7.4 miles) ⓘLinkpot cut, Airline Railroad, East Hampton, Middlesex County, Connecticut, USA
12.3km (7.6 miles) ⓘGreat Hill cobalt mines, Cobalt, East Hampton, Middlesex County, Connecticut, USA
References
Seaman, David M. and Robert P. Gallant (1960): SPESSARTITE GARNET WITH HEXOCTAHEDRAL FACES FROM JAIL HILL, HADDAM, CONNECTICUT Rocks & Minerals, Vol. 35, Nos. 9-10, pp. 445-8.
 
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