Natrolite
Species
Uncommon · Na₂[Al₂Si₃O₁₀]•2(H₂O)
A sodium zeolite in radiating sprays of fine needles lining gas cavities in basalt. Before the blowpipe it turns white and opaque as its loosely held water is driven off, then fuses quietly to a clear glass.
Identity
- Formula
- Na₂[Al₂Si₃O₁₀]•2(H₂O)
- Chemical class
- Silicate
- Mineral group
- Analcime, Heulandite, Stilbite
- Also known as
- Needle zeolite
Crystallography
- Crystal system
- Orthorhombic
- Habits
- Acicular, Prismatic, Fibrous, Massive
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 5.5
- Density
- 2.25 g/cm³
- Luster
- Silky, Vitreous
- Colors
- white, colorless, red, yellowish white, reddish white
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Igneous, Hydrothermal
- Host rocks
- Granite, Volcanic rock
- Associated minerals
- Analcime, Heulandite, Calcite, Benitoite
- Geography
- Czech Republic, India, USA
Classification
- Rarity
- Uncommon
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- Natrolite. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Natrolite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
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