Mineral description : Gypsum

Small crystals of gypsum from Kvinnesta.

Mineral class Sulphates : Anhydrite - Gypsum group.

Chemical formula Ca(SO₄)^.2H₂O

Crystal system Monoclinic.

Habitus Tabular or elongated crystals. Aggregates in the form of roses are called desertroses. Also radiating fibric aggregates. Twinning is common in the form of swallow tails. Grainy or compact aggregates are also common.

Cleavage Perfect, creating thin fragments.

Hardness 2

Density 2.35

Color White to yellowish white.

Streak

Luster Vitreous to pearly. Transparent to translucent.

Description

Occurance In evaporite deposits or deposits around hot springs.
In Sweden the main occurance is in old mine dumps and mineshafts. A product from oxidised pyrite.

Associates

Notes Transparent crystals and fragments are called selenite.
Dense banded varietys are called alabaster.
Soluble in hydrochloric acid and hot water.
Could show fluorescens.

Locations Common on old mine dumps at sulphide mines.

Falu mine, Dalarna. On the walls of old mine shafts.
Stollgruvan, Västra Silfberg, Dalarna. In the dump pile of sulphide ore.
Solberga Limestone quarry, Boda, Dalarna. On the walls, resulting from oxidation of marcasite.
Långban, Värmland. As fracture fillings.
Harstigen, Persberg, Värmland. As fracture fillings.

To sulphates index.
Mineral group index.
Main index.

If you have some questions, suggestions or comments you are welcome to write me a line or two.

axelsson@acc.umu.se

To my homepage.
Last changed : 1998-09-09

Mineral class	Sulphates : Anhydrite - Gypsum group.
Chemical formula	Ca(SO₄)^.2H₂O
Crystal system	Monoclinic.
Habitus	Tabular or elongated crystals. Aggregates in the form of roses are called desertroses. Also radiating fibric aggregates. Twinning is common in the form of swallow tails. Grainy or compact aggregates are also common.
Cleavage	Perfect, creating thin fragments.
Hardness	2
Density	2.35
Color	White to yellowish white.
Streak
Luster	Vitreous to pearly. Transparent to translucent.
Description
Occurance	In evaporite deposits or deposits around hot springs. In Sweden the main occurance is in old mine dumps and mineshafts. A product from oxidised pyrite.
Associates
Notes	Transparent crystals and fragments are called selenite. Dense banded varietys are called alabaster. Soluble in hydrochloric acid and hot water. Could show fluorescens.
Locations	Common on old mine dumps at sulphide mines. Falu mine, Dalarna. On the walls of old mine shafts. Stollgruvan, Västra Silfberg, Dalarna. In the dump pile of sulphide ore. Solberga Limestone quarry, Boda, Dalarna. On the walls, resulting from oxidation of marcasite. Långban, Värmland. As fracture fillings. Harstigen, Persberg, Värmland. As fracture fillings.