Mineral description : Natrolite

Natrolite from Långban, Värmland.

Mineral class Silicates : Tekto silicates : Zeolites

Chemical formula Na₂Al₂Si₃O₁₀*2H₂O

Crystal system Orthorombic

Habitus As thin needlelike crystals in diverging or radiating groups, also as global, concentric shells, thready, derb, thick or mealy.

Cleavage Perfect, brittle.

Hardness 5-5.5

Density 2.2-2.26

Color Usually white to colorless, but nuances in yellow and pink.

Streak White.

Luster glas to pearly, silky on fibrous variants.

Description

Occurance Usually found in cavities in volcanic rocks, but also as a transformation product of nefeline and plagioklase.

Associates Other zeolites, calcite.

Similar minerals Mesolite, scolesite.

Notes Soluble in strong acids. Yellow staining of a flame.

Locations A rare mineral in Sweden.

Gubbnehall basalt mine, Ynglingarum, Skåne. As fibric veins and crack fillings.
Alnön, as transformation of nefeline. (Hörningsholm...)
Långban, as stalky and mealy aggregates in cracks in green scarn.
Fröå mine, Jämtland. As small beautiful crystals.

To silicate 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

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Last changed : 1998-03-07

Mineral class	Silicates : Tekto silicates : Zeolites
Chemical formula	Na₂Al₂Si₃O₁₀*2H₂O
Crystal system	Orthorombic
Habitus	As thin needlelike crystals in diverging or radiating groups, also as global, concentric shells, thready, derb, thick or mealy.
Cleavage	Perfect, brittle.
Hardness	5-5.5
Density	2.2-2.26
Color	Usually white to colorless, but nuances in yellow and pink.
Streak	White.
Luster	glas to pearly, silky on fibrous variants.
Description
Occurance	Usually found in cavities in volcanic rocks, but also as a transformation product of nefeline and plagioklase.
Associates	Other zeolites, calcite.
Similar minerals	Mesolite, scolesite.
Notes	Soluble in strong acids. Yellow staining of a flame.
Locations	A rare mineral in Sweden. Gubbnehall basalt mine, Ynglingarum, Skåne. As fibric veins and crack fillings. Alnön, as transformation of nefeline. (Hörningsholm...) Långban, as stalky and mealy aggregates in cracks in green scarn. Fröå mine, Jämtland. As small beautiful crystals.