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 incorrectDark 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.
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Physical properties
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.
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.
