Natrolite Gem Guide and Properties Chart

Natrolite is a zeolite mineral named for the Greek word natron, meaning "soda," due to the presence of sodium in the stone. Its range of colors include yellow, gray, and brown, to colorless. Occasionally, it is found in pale yellow to red hues. Crystals often grow in long, needle-like formations, and are especially prized by specimen collectors.

General Information

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

Common Name

Natrolite

Species

Natrolite

Transparency

Transparent - Opaque

Dispersion

Strength: Weak Fire Value: 0.005

Refractive Index

1.480-1.493

Birefringence

0.012-0.013

Optic Character

Biaxial

Optic Sign

Positive

Polariscope Reaction

Aggregate (AGG), Doubly Refractive (DR)

Fluorescence

SWUV: Inert to strong green
LWUV: Inert to weak greenish white

Pleochroism

Unobservable

Hardness

5-5.5

Streak

White

Specific Gravity

2.200-2.260

Toughness

Poor

Inclusions

Natrolite is usually found as a fibrous aggregate. Stones might have yellowish brown acmite inclusions that appear rod-like.

Luster

Vitreous, Silky

Fracture

Uneven

Cleavage

Perfect, in one direction

Chemical Name

hydrated sodium aluminum silicate

Chemical Formula

Na₂[Al₂Si₃O₁₀].₂H₂O

Crystal System

Orthorhombic

Chemistry Classification

Silicate

Natrolite Colors

Blue
Brown
Colorless
Gray
Pink
White
Yellow

Countries of Origin

Russian Federation; Unknown; United States of America

Care

Natrolite is brittle so take extra care when handling.