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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, 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.

Natrolite Polished
Natrolite Classification
Common Name Natrolite
Species Natrolite
Natrolite Optical Properties
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
Natrolite Characteristic Physical Properties
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
Natrolite Chemistry & Crystallography
Chemical Name hydrated sodium aluminum silicate
Chemical Formula Na2[Al2Si3O10].2H2O
Crystal System Orthorhombic
Chemistry Classification Silicate

Natrolite Colors

  • Yellow Natrolite Yellow
  • White Natrolite White
  • Brown Natrolite Brown
  • Colorless Natrolite Colorless
  • Gray Natrolite Gray
  • Pink Natrolite Pink
  • Blue Natrolite Blue

Countries of Origin

United States of America (the); Unknown; Russian Federation (the)

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.