mineral

Fuchsite

Chromian Muscovite, K(Al,Cr)2(AlSi3O10)(OH)2

AI-generated identification · may be incorrect

Hardness: 2-3. Color: green to emerald green. Luster: Pearly to vitreous. Crystal structure: Monoclinic. Cleavage: Perfect on {001}. Specific gravity: 2.7-3.0.

Hardness: 2-3
Color: green to emerald green
Luster: Pearly to vitreous

Identified July 24, 2026More mineral →

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Physical properties

Hardness: 2-3. Color: green to emerald green. Luster: Pearly to vitreous. Crystal structure: Monoclinic. Cleavage: Perfect on {001}. Specific gravity: 2.7-3.0.

Formation & geological history

Forms in metamorphic rocks such as schists and gneisses, replacing other minerals like plagioclase or orthoclase during regional or contact metamorphism. Chromium substitutes for aluminum in the muscovite structure.

Uses & applications

Primarily collected as a mineral specimen. Sometimes used in jewelry as cabochons, often when included in quartz (green aventurine) or with ruby (ruby in fuchsite). Historically used as a green pigment.

Geological facts

Named in 1842 by Karl F. E. Schafhäutl in honor of Johann Nepomuk von Fuchs, a German chemist and mineralogist. When it occurs with ruby, it creates a striking contrasting stone often misidentified as ruby in zoisite (anyolite).

Field identification & locations

Identified by its distinctive green color, platy or flaky habit (typical of micas), and perfect cleavage allowing it to be separated into thin, flexible sheets. Found in locations like Brazil, India, Russia, and the USA.