Mineral description : Zoisite

Zoisite from Bleikvatnet, Norway.

Thulite from Lom, Norway. Thulite from Högtuva, Norway. Thulite from Lervik, Norway.

Mineral class Silicates : Sorosilicates : Epidot - Vesuvianite group.

Chemical formula Ca₂Al₃(O/OH/SiO₄/Si₂O₇)

Crystal system Orthorombic.

Habitus Prismatic, columnar crystals, often striated. Commonly in massive aggregates.

Cleavage [001] Perfect, fracture even.

Hardness 6-6.5

Density 3.3

Color Gray, greenish to light red, blue (tanzanite) or pink.

Streak White.

Luster Vitreous to pearly. Dull on finegrained aggregates.

Description Used as an ornamental stone.

Occurance In metamorphic rocks and pegmatites.

Associates

Notes A pink manganeese containing variety is called thulite and is the national stone of Norway.
Strongly pleochroic.
Insoluble in acids.
Named after the Austrian scientist S Zois.
Type locality : Rauris and Saualpe, Austria.
A clear green variety is associated with rubies.
A gemmy blue variety with high strontium contents is found in Tanzania. It is called tanzanite and very sought after as a gemstone.

Locations A not so common mineral in Sweden.

Falu mine, Falun, Dalarna. Massive light red.
Vena mine, Örebro.
Vintjärn mine, Dalarna.
Lainijauri, Lappland.
Norway :

Bleikvatnet, Mo i Rana, Norway. As brownish green crystals in veins in amphibolite.

To silicate index.
Mineral group index.
Main index.

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axelsson@acc.umu.se

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Last changed : 1998-09-16

Mineral class	Silicates : Sorosilicates : Epidot - Vesuvianite group.
Chemical formula	Ca₂Al₃(O/OH/SiO₄/Si₂O₇)
Crystal system	Orthorombic.
Habitus	Prismatic, columnar crystals, often striated. Commonly in massive aggregates.
Cleavage	[001] Perfect, fracture even.
Hardness	6-6.5
Density	3.3
Color	Gray, greenish to light red, blue (tanzanite) or pink.
Streak	White.
Luster	Vitreous to pearly. Dull on finegrained aggregates.
Description	Used as an ornamental stone.
Occurance	In metamorphic rocks and pegmatites.
Associates
Notes	A pink manganeese containing variety is called thulite and is the national stone of Norway. Strongly pleochroic. Insoluble in acids. Named after the Austrian scientist S Zois. Type locality : Rauris and Saualpe, Austria. A clear green variety is associated with rubies. A gemmy blue variety with high strontium contents is found in Tanzania. It is called tanzanite and very sought after as a gemstone.
Locations	A not so common mineral in Sweden. Falu mine, Falun, Dalarna. Massive light red. Vena mine, Örebro. Vintjärn mine, Dalarna. Lainijauri, Lappland. Norway : Bleikvatnet, Mo i Rana, Norway. As brownish green crystals in veins in amphibolite.