Sodalite
Species
Uncommon · Na₈(Al₆Si₆O₂₄)Cl₂
A sodium aluminium silicate chloride found in silica-undersaturated igneous rocks such as nepheline syenites and phonolites. Its blue comes from defects in the crystal lattice, not from iron, and a freshly broken piece may smell of hydrogen sulfide. Displays strong red-orange fluorescence under ultraviolet light.
Identity
- Formula
- Na₈(Al₆Si₆O₂₄)Cl₂
- Chemical class
- Silicate
- Mineral group
- Hauyne, Lapis Lazuli, Lazurite
Crystallography
- Crystal system
- Cubic
- Habits
- Massive, Dodecahedral, Granular
- Fracture
- Conchoidal
Physical properties
- Mohs hardness
- 5.5
- Density
- 2.3 g/cm³
- Luster
- Vitreous, Waxy
- Colors
- blue, dark blue, gray-blue, white
- Streak
- white
- Transparency
- Translucent, Opaque
Geology
- Origins
- Igneous, Metamorphic
- Host rocks
- Granite, Volcanic rock, Marble
- Associated minerals
- Nepheline, Cancrinite, feldspar
- Geography
- Canada (Ontario, Quebec, British Columbia), Greenland, Bolivia (Cochabamba), Russia (Kola Peninsula), Norway, USA (Maine, Arkansas)
Classification
- Rarity
- Uncommon
- Gem quality
- Yes
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.
- Sodalite. Mindat.org (Hudson Institute of Mineralogy).
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Sodalite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Sodalite. Gemdat.org (Hudson Institute of Mineralogy).
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