Tremolite
Species
Uncommon · Ca₂Mg₅Si₈O₂₂(OH)₂
Calcium magnesium amphibole forming in metamorphosed dolomitic marbles. The rare purple hexagonite variety is coloured by manganese. Fibrous tremolite is a form of asbestos.
Identity
- Formula
- Ca₂Mg₅Si₈O₂₂(OH)₂
- Chemical class
- Silicate
- Mineral group
- Actinolite, Hornblende, Nephrite, Richterite
- Also known as
- Hexagonite (purple variety), Grammatite
Crystallography
- Crystal system
- Monoclinic
- Habits
- Prismatic, Bladed, Fibrous, Massive
- Fracture
- Splintery
Physical properties
- Mohs hardness
- 5.5
- Density
- 2.99 g/cm³
- Luster
- Vitreous, Silky
- Colors
- white, gray, pale green, pink, colorless
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Metamorphic
- Host rocks
- Ultramafic rock (peridotite, serpentinite), Marble, Limestone and chalk
- Associated minerals
- Calcite, Dolomite, Diopside, Talc
- Found in
- Nephrite, Soapstone
- Geography
- Switzerland, Italy, USA, Canada, Tanzania
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.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Tremolite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Tremolite: Mineral information, data and localities. mindat.org.
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