Natrolite

Formula: Na2Al2Si3O10·2H2O

References

  1. https://en.wikipedia.org

  2. https://www.washingtonminerals.com/rp.htm

Mohs scale hardness: 5–6Specific gravity: 2,25

It is decomposed by hydrochloric acid with separation of gelatinous silica.

Natrolite is a tectosilicate mineral species belonging to the zeolite group. Natrolite occurs with other zeolites in the amygdaloidal cavities of basaltic igneous rocks. It is also common in nepheline syenites.

Notable localities

Excellent specimens of diverging groups of white prismatic crystals are found in compact basalt at the Puy-deMarman, Puy-de-Dôme, France, the Kola Peninsula, Russia, north of Bohemia, Quebec, the Bay of Fundy in Nova Scotia, New Jersey, Oregon, and British Columbia.

Fargite is a red natrolite from Glenfarg in Perthshire. Bergmannite, or Spreustein, is an impure variety which has resulted by the alteration of other minerals, chiefly sodalite, in the augite syenite of southern Norway.