mineral

Tumbled green aventurine (likely)

Quartzite dominated by quartz (SiO₂), colored by fuchsite mica and/or chlorite

AI-generated identification · may be incorrect

Typically Mohs 6.5–7, green, translucent to opaque, with a vitreous-to-waxy luster and irregular conchoidal fractures; faint aventurescence may appear as glittery reflections. Individual pieces are polished/tumbled rather than naturally crystallized specimens.

Identified August 23, 2026More mineral →

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Physical properties

Formation & geological history

Aventurine forms when quartz-rich rock recrystallizes and incorporates green chromium-bearing mica or chlorite, commonly during metamorphism. Deposits are found in India, Brazil, Russia, Tanzania, and elsewhere; precise age depends on locality.

Uses & applications

Used for beads, carvings, cabochons, ornamental objects, and inexpensive collectible tumbled stones; occasionally used as decorative aggregate.

Geological facts

The name refers to aventurescence, a sparkly optical effect caused by reflective inclusions. Much commercial “green aventurine” is subtly glittery, while uniformly dark pieces may instead be serpentine, green chalcedony, or dyed quartzite.

Field identification & locations

Identify by hardness, quartz-like translucency, and mica sparkle; it should scratch glass but not be scratched by a steel knife. Value is usually about $3–$15 for a small lot, or $10–$40 for attractive polished specimens.