Green amphibole mineral forming the intermediate member between tremolite and ferro-actinolite. Nephrite jade is a compact variety. Color: Green to dark green. Luster: Vitreous to silky. Streak: White. Cleavage: Good in two directions at 56°. Hardness: 5-6. Transparency: Translucent to opaque. Crystal system: Monoclinic. Chemical formula: Ca₂ Mg,Fe ₅Si₈O₂₂ OH ₂. Specific gravity: 3.0-3.4. Formation: Forms during low to medium grade metamorphism of mafic rocks, characteristic of the greenschist facies. Common geological settings: Worldwide; found in greenschist-facies metamorphic rocks. Nephrite jade from British Columbia, New Zealand, China. Common look-alikes and related entries: Hornblende, Tremolite, Epidote.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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GeoMiner
Last updated
2026-03-30T14:36:46.075255+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Green amphibole mineral forming the intermediate member between tremolite and ferro-actinolite. Nephrite jade is a compact variety.
How can you identify Actinolite?
Compare several properties rather than relying on colour alone. This entry records colour: Green to dark green; lustre: Vitreous to silky; streak: White; Mohs hardness: 5-6; cleavage: Good in two directions at 56°; crystal system: Monoclinic; transparency: Translucent to opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Actinolite form?
Forms during low to medium grade metamorphism of mafic rocks, characteristic of the greenschist facies.
Where is Actinolite commonly found?
Worldwide; found in greenschist-facies metamorphic rocks. Nephrite jade from British Columbia, New Zealand, China.
What is Actinolite commonly confused with?
Actinolite may be confused with Hornblende, Tremolite, Epidote. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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