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Biotite series

#PD34672
SOLD
Biotite from Franklin, Sussex Co., New Jersey, United States - PD34672
Biotite from Franklin, Sussex Co., New Jersey, United States - PD34672

Biotite series

#PD34672
Availability
Sold
Size
6 x 4.5 x 4 cm - Sm Cabinet 
Formula
Unavailable
Locality
Franklin, Sussex Co., New Jersey, United States

Phyllosilicate - Monoclinic - Mica group member. Ordinary (True or Common) Mica - Trioctahderal. For more information on Mica minerals and other phyllosilicates please reference our article - Click Here.

Biotite has historically been treated as an individual mineral species and also treated as a generic dark mica in the field for those geologist without the aid of a portable XRD, which none of us had. Rieder et. al in the Canadian Mineralogist v. 36 (1998), reclassified and placed Biotite within the Annite-Phlogopite series..

This specimen is just a nice chunk with serious dark cleavage planes.

Biotite

Formula
K(Mg,Fe++)3[AlSi3O10(OH,F)2 
Crystal System
Monoclinic 
Crystal Habit
Micaceous, Lamellar, Pseudo Hexagonal 
Cleavage
Perfect, None, None 
Luster
Vitreous - Pearly 
Color
dark brown, greenish brown, blackish brown, yellow, white 
Streak
gray 
Class
Monoclinic - Prismatic 
Fracture
Uneven 
Hardness
2.5-3 

Data courtesy of Webmineral.

Collection
Phillips Collection
Mineralpedia
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On Dakota Matrix
Previously Sold Biotite
On Dakota Matrix
Other Available Biotite
WebMineral
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Mindat
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Other Sold

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