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Muscovite (var. Fuchsite) identification and geology
Chromium-bearing variety of muscovite mica with a distinctive emerald-green color. Often found in aventurine quartz. Color: Emerald green. Luster: Vitreous to pearly. Streak: White. Cleavage: Perfect basal. Hardness: 2-2.5. Transparency: Transparent to translucent. Crystal system: Monoclinic. Chemical formula: K Al,Cr ₂ AlSi₃O₁₀ OH ₂. Specific gravity: 2.77-2.88. Formation: Forms in chromium-rich metamorphic rocks, particularly in altered ultramafic rocks. Common geological settings: India, Brazil, Russia, Zimbabwe; found in metamorphic rocks associated with chromium. Common look-alikes and related entries: Muscovite, Chlorite, Verdite.
Sources, scope & corrections
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.
- Editorial owner
- GeoMiner
- Last updated
- 2026-02-10T20:25:54.470219+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.
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