Anthophyllite- Encyclopedia

    Class : Silicates
    Subclass : Inosilicates
    Crystal System : Orthorhombic
    Chemistry : (Mg,Fe)7Si8O22(OH)2
    Rarity : Uncommon

Anthophyllite belongs to the group of orthorhombic amphiboles and forms two series with ferro-anthophyllite and magnesio-anthophyllite. It is a typical amphibole of metasomatic magnesian rocks, in metamorphic rocks of medium to strong gradient (gneiss, amphibolite, metaquartzite, granulite) and more rarely in schistous formations derived from clayey sediments or basic to ultrabasic magmatic rock (peridotites, serpentines, etc...). Its name comes from the Latin anthophyllum (clove), due to its brown color. It generally occurs in fibrous, asbestiform masses, reaching 25 cm, then called amosite but also qualified as brown asbestos. It rarely occurs in crystals in the form of orthorhombic prisms, of a brownish-green to brownish-grey and brown color. It is commonly polished and used as an ornamental or jewelry stone, while in the form of asbestos it was used as a fireproof material, thermal and electrical insulation panels, etc...

Anthophyllite in the World

The most classic anthophyllite localities are Kongsberg (Norway), Dürrenstein (Austria), Kangerluarsuk (Greenland), Hermanov (Czech Republic), and the Wakefield pegmatite (Quebec) which yielded long prismatic crystals. Asbestiform anthophyllite is known in several localities in the USA : Kamia (Idaho), Sall Mount (Georgia) and Carrville (California) as well as in South Africa.

Photo on the right : anthophyllite from Paakkila Mine, Finland © Jyirki Autio

Anthophyllite in France

In France, anthophyllite is found in attractive fibrous masses at Allevier (Haute-Loire) in a serpentinized peridotite, but also in the former talc quarry of Séchier (Hautes-Alpes).


No known twins for this mineral species.

Fakes and treatments

No fake recorded for this mineral species, but often confused with astrophyllite (much rarer) on the mineral market.

Hardness :  5.5 to 6
Density : 2.85 to 3.37
Fracture : Conchoidal
Trace : White to gray

TP : Translucent to transparent
RI : 1.598 to 1.697
Birefringence : 0.017 to 0.023
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : Hydrofluoric acid

Magnetism : Paramagnetic
Radioactivity : None