Stilbite

Real mineral · common · NaCa₄(Si₁₆Al₆)O₄₂·2H₂O

A zeolite group mineral forming sheaf-like aggregates of tabular crystals in the vesicles of volcanic basalt. Formed by low-temperature hydrothermal alteration. Among the most common and widely distributed zeolite minerals.

Identity

Formula

NaCa₄(Si₁₆Al₆)O₄₂·2H₂O

Chemical class

silicate

Mineral group

Analcime, Heulandite, Natrolite

Also known as

Desmine (archaic), Stellerite

Crystallography

Crystal system

monoclinic

Habits

tabular, sheaf-like aggregates

Fracture

uneven

Physical properties

Mohs hardness

3.5

Density

2.2 g/cm³

Luster

vitreous, pearly

Colors

colorless, white, pink, yellow, orange

Streak

white

Transparency

transparent, translucent

Geology

Origins

hydrothermal

Host rocks

basalt, andesite

Associated minerals

Heulandite, Apophyllite, Calcite, Prehnite

Geography

India, Iceland, USA, Canada, Brazil

Classification

Rarity

common

Gem quality

No

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