Fuchsite Gneiss (Green Quartzite)

Physical Properties

Hardness: 6-7 (if quartz-heavy) or 2-3 (if pure mica); Color: Emerald green to silvery-green; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal.

Formation & Geological History

Formed through regional metamorphism of clay-rich sediments or ultra-mafic rocks where chromium is present. The green color is derived from small amounts of trivalent chromium replacing aluminum in the mica structure.

Uses & Applications

Used primarily as an ornamental stone, in the production of 'Green Aventurine' jewelry when included in quartz, and as a collector's specimen.

Geological Facts

Fuchsite is often associated with gold deposits; in some regions, it is known as 'Mariposite' when appearing in dolomitic marble. It is the chromium variety of common muscovite mica.

Field Identification & Locations

Identify by its distinct emerald-green flaky appearance and its tendency to sparkle (micaceous luster). Commonly found in Precambrian metamorphic terrains, especially in Brazil, India, and Russia.

Identified on: 4/14/2026

Mode: Standard