mineral

Tumbled green aventurine

Quartz (SiO₂), microcrystalline variety colored mainly by fuchsite mica or chromium-bearing inclusions

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent to opaque green, vitreous to waxy luster, granular cryptocrystalline quartz, and no obvious cleavage. The polished oval is a tumbled/cabochon specimen with subtle inclusions and surface pits.

Identified September 14, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids crystallize as quartzite or chalcedonic quartz containing green fuchsite or chromium mica; most material is Precambrian to Paleozoic in age. Common sources include India, Brazil, Russia, and Tanzania.

Uses & applications

Used for inexpensive cabochons, beads, carvings, ornaments, and lapidary items; occasionally used decoratively as stone tile or aggregate.

Geological facts

Aventurine is named for aventurescence, a glittering reflection from platy inclusions, though this specimen shows little visible sparkle. It is often confused with dyed quartz or green glass.

Field identification & locations

Identify by its quartz-like hardness, cool feel, granular texture, and possible mica sparkle; it should scratch ordinary glass but not be scratched by a steel knife. Common tumbled pieces typically sell for $2–$15; larger, attractive cabochons may bring $10–$40.