mineral

Tumbled blue stone, likely blue aventurine or dyed chalcedony

Aventurine quartz (SiO₂) or chalcedony (microcrystalline SiO₂); exact identification requires testing

AI-generated identification · may be incorrect

Dark blue, smoothly polished, with vitreous-to-waxy luster and faint internal sparkle or veining. Quartz hardness is about 7 Mohs; specific gravity is approximately 2.6, with no visible cleavage and conchoidal fracture.

Identified August 25, 2026More mineral →

Explore Tumbled blue stone, likely blue aventurine or dyed chalcedony in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Natural quartz varieties form in silica-rich hydrothermal veins or cavities; blue color may result from inclusions, or from artificial dyeing. The rounded shape indicates human tumbling, not a natural rock texture.

Uses & applications

Used as a lapidary stone, decorative pebble, jewelry cabochon, and collectible. Common commercial pieces are inexpensive.

Geological facts

Blue aventurine is often colored by dumortierite or other inclusions, while strongly uniform blue stones are frequently dyed. The photograph alone cannot distinguish these possibilities reliably.

Field identification & locations

Common sources include India, Brazil, Russia, and Madagascar. Check hardness, dye concentration in cracks, and translucency; a streak, magnification, and specific-gravity test help separate quartz from glass or dyed stone.