Diagnostic Features

Hardness: 2-2.5
Streak: White to none.
Luster: Nonmetallic
Specific Gravity: 2.8
Cleavage: Present in one direction.
Fracture: None
Other: Mineral separates into perfectly parallel sheets.


Identification Tips

1.  Biotite, like the other types of mica, consist of seemingly endless, flexible, transparent sheets. Therefore, mica crystals are referred to as "books." You can separate the sheets easily with your fingernail
2.  Biotite possesses a black to dark brown sheen and this distinguishes it from other common mica types. Light passing through a single thin sheet of biotite resembles light passing through a weak sunglass lens.

Photographed by Michael Amadeus Klimetz
Biotite
Single Crystal

Otter Lake

Quebec
CANADA
Photographed by Michael P. Klimetz
Photographed by Michael P. Klimetz
Photographed by Michael P. Klimetz
[Crystals in Calcite]

CANADA
Sterling Hill Mine

Ogdensburg

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


Kero's [Tilcon] Quarry

Byram Township

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


Kero's [Tilcon] Quarry

Byram Township

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


Kero's [Tilcon] Quarry

Byram Township

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


Kero's [Tilcon] Quarry

Byram Township

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


Kero's [Tilcon] Quarry

Byram Township

Sussex County
NEW JERSEY
Photographed by Michael P. Klimetz


[With Sodalite]

Bancroft Area

Ontario
CANADA
Photographed by Michael P. Klimetz


[With Sodalite]

Bancroft Area

Ontario
CANADA
Photographed by Michael P. Klimetz


[With Sodalite]

Bancroft Area

Ontario
CANADA
Photographed by Michael P. Klimetz


[With Sodalite]

Bancroft Area

Ontario
CANADA
Photographed by Michael P. Klimetz


[With Sodalite]

Bancroft Area

Ontario
CANADA
Photographed by Michael P. Klimetz


[Crystal Plates in Pegmatite with Muscovite]

Julianna Pegmatite
DSS Piława Górna Quarry

Lower Silesia
POLAND
Photographed by Michael P. Klimetz


[Crystal Plates in Pegmatite with Muscovite]

Julianna Pegmatite
DSS Piława Górna Quarry

Lower Silesia
POLAND
Photographed by Michael P. Klimetz


[Crystal Plates in Pegmatite with Muscovite]

Julianna Pegmatite
DSS Piława Górna Quarry

Lower Silesia
POLAND
Photographed by Michael P. Klimetz


[Crystal Plates in Pegmatite with Muscovite]

Julianna Pegmatite
DSS Piława Górna Quarry

Lower Silesia
POLAND