Biotite

Origin: Sattleberg, Laacher See, Rheinland-Pfalz, Germany

Owner: Lou Perloff

Microscopic image

 

Origin: Bellerberg quarry, Laacher See, Rheinland-Pfalz, Germany

Owner: Lou Perloff

Microscopic image

 

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Photo-Atlas of Minerals

3 mm group of biotite crystals coated by clinochlore

Origin: Eas a Bradain, Luib, Isle of Skye, Inverness-shire, North West Highlands, Scotland, UK

Owner: Steve Rust

 

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This specimen is comprised of essentially solid biotite. Manganophyllite is the name for this manganese rich form of biotite.

  

This specimen has books of biotite to just under 1 cm across. Manganophyllite is the name for this manganese rich form of biotite. The matrix consists of calcite and what appears to be either hornblende or another manganese oxide such as hausmannite.

Origin: Långban, Sweden

Harry von Eckermann Collection

Sample size: 6 x 2.5 x 2.5 cm (top), 10 x 6 x 3.5 cm (bottom)

 

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Origin: Emmelberg, Eifel, Germany

Sample size: 3 x 6 cm

 

Origin: San Vito quarry, Vesuvius, Napoli, Italy

Sample size: 3 x 5 cm

 

Mica-quartzite with 1-3 mm large brown biotite porphyroblasts

Origin: Bäfverbäcken, Borkafjäll, Lapland, Sweden

Sample size: 5.5 x 10 cm

 

Origin: Ås, Evje, Setesdalen, Aust-Agder, Norway

Sample size: 2 x 4 x 15 cm

 

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Biotite pseudomorph after tourmaline

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