Mineral description : Actinolite

Actinolite crystals in talc from Altemark talc mine, Norway. Dark green actinolite crystals in talc and magnesite Altemark talc mine, Norway.

Mineral class Silicates : Inosilicates : Tremolite - Glaucophane - Riebeckite group.

Chemical formula Ca₂(Mg,Fe)₅(OH,F,Si₄O₁₁)₂

Crystal system Monoclinic.

Habitus Thin long prismatic crystals. Also common as needle thin aggregates and fibrous aggregates (asbesthos)

Cleavage Perfect in two directions with 124 degrees angle.

Hardness 5-6

Density 3.1-3.3

Color Dark green, darker than tremollite.

Streak

Luster

Description

Occurance In hydrothermally metamorphed magmatic rocks. In metamorph scarns.

Associates

Notes

Locations A very common mineral in many Swedish mines.

Kallmoraberg, Norberg, Västmanland. As nice dark green crystals.
Riddarhyttan, Västmanland.
Falu copper mine, Falun, Dalarna.
Altemark, Mo i Rana, Norway. As dark green crystals in talc.

To silicate index.
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Last changed : 1998-12-29

Mineral class	Silicates : Inosilicates : Tremolite - Glaucophane - Riebeckite group.
Chemical formula	Ca₂(Mg,Fe)₅(OH,F,Si₄O₁₁)₂
Crystal system	Monoclinic.
Habitus	Thin long prismatic crystals. Also common as needle thin aggregates and fibrous aggregates (asbesthos)
Cleavage	Perfect in two directions with 124 degrees angle.
Hardness	5-6
Density	3.1-3.3
Color	Dark green, darker than tremollite.
Streak
Luster
Description
Occurance	In hydrothermally metamorphed magmatic rocks. In metamorph scarns.
Associates
Notes
Locations	A very common mineral in many Swedish mines. Kallmoraberg, Norberg, Västmanland. As nice dark green crystals. Riddarhyttan, Västmanland. Falu copper mine, Falun, Dalarna. Altemark, Mo i Rana, Norway. As dark green crystals in talc.