mineral

Tumbled blue chalcedony or dyed quartz

Microcrystalline quartz, SiO₂ (likely dyed chalcedony)

AI-generated identification · may be incorrect

Vivid turquoise-blue, translucent to opaque, waxy-to-glassy luster, cryptocrystalline structure, no visible cleavage, conchoidal fracture, Mohs hardness about 6.5–7, specific gravity ~2.6. The unusually saturated color and cloudy zoning suggest dye treatment; it may also be blue quartz or dyed agate.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; deposition ranges from ancient to modern. Tumbled pieces are mechanically polished, and dye may be introduced through porous microfractures.

Uses & applications

Used as inexpensive beads, cabochons, ornaments, and lapidary material; normally sold as a decorative stone rather than a high-value gemstone.

Geological facts

Natural blue chalcedony is uncommon, while dyed blue agate/chalcedony is widespread. Color may concentrate along cracks or in porous zones.

Field identification & locations

Check for dye pooling in fractures, color rubbing or bleeding with acetone, and hardness sufficient to scratch glass; glass imitations may show bubbles and are softer. Common sources include Brazil, Uruguay, India, Madagascar, and China.