Actinolite
Species
Common · Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂
Calcium magnesium iron amphibole forming in low to medium grade metamorphic rocks. The massive nephrite jade variety is one of the two minerals sold as jade. Fibrous actinolite is a recognised asbestos mineral.
Identity
- Formula
- Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂
- Chemical class
- Silicate
- Mineral group
- Hornblende, Nephrite, Richterite, Tremolite
- Also known as
- Nephrite jade (massive variety), Byssolite (fibrous)
Crystallography
- Crystal system
- Monoclinic
- Habits
- Prismatic, Bladed, Fibrous, Massive
- Fracture
- Splintery
Physical properties
- Mohs hardness
- 5.5
- Density
- 3.04 g/cm³
- Luster
- Vitreous, Silky
- Colors
- green, dark green, gray-green, black
- Streak
- white
- Transparency
- Transparent, Translucent
Geology
- Origins
- Metamorphic
- Host rocks
- Schist and gneiss, Marble
- Associated minerals
- Tremolite, Chlorite, Epidote, Albite
- Found in
- Nephrite, Skarn
- Geography
- Canada, New Zealand, Taiwan, China, Russia
Classification
- Rarity
- Common
- 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, Actinolite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Nephrite. Gemdat.org (Hudson Institute of Mineralogy).
- Actinote (minéral). Wikipédia, l'encyclopédie libre.
- Actinolite: Mineral information, data and localities. mindat.org.
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