Stilbite Gem Guide and Properties Chart

Stilbite

By Tim Matthews, JD, FGA, GG, DGA,
CEO and President of JTV (retired)

Published: June 2014

Stilbite is named from a Greek term meaning "to glitter" due to the pearly luster of the mineral. A member of the zeolite group, stilbite is often white, peach, pinkish, yellow or brown in color. Stilbite is further classified based on its sodium and calcium content. Stilbite is rarely faceted, but its attractive crystals make it highly collectable as mineral specimens

General Information

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

Common Name

Stilbite

Species

Stilbite

Transparency

Transparent - Opaque

Dispersion

Strength: Weak Fire

Refractive Index

1.484-1.513

Birefringence

0.01-0.013

Optic Character

Biaxial

Optic Sign

Negative

Polariscope Reaction

Aggregate (AGG), Doubly Refractive (DR)

Fluorescence

SWUV: Inert
LWUV: Inert

Pleochroism

Unobservable

Hardness

3.5-4

Streak

White

Specific Gravity

2.100-2.200

Toughness

Poor

Luster

Vitreous, Pearly

Fracture

Conchoidal

Cleavage

Perfect, in one direction

Chemical Formula

NaCa₄(Si₂₇Al₉)O₇₂ ₂₈(H₂O)

Crystal System

Monoclinic

Chemistry Classification

Silicate

Stilbite Colors

Brown
Colorless
Gray
Multi-color
Orange
Pink
Red
White
Yellow

Alternate Names

Desmine, Stilbite-Ca

Countries of Origin

Canada; Russian Federation; Unknown; United States of America; Brazil; India

Care

Soluble in hydrochorlic acid