gemstone

Dyed blue chalcedony (likely dyed quartz pebble)

Chalcedony, microcrystalline quartz (SiO₂), artificially colored

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; vivid opaque-to-translucent blue color, waxy to vitreous luster, cryptocrystalline structure, and no visible cleavage. Rounded and polished, with possible natural inclusions or dye concentration in pores and fractures.

Identified August 28, 2026More gemstone →

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Physical properties

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures, commonly in volcanic rocks; its geological age varies widely. The intense uniform blue color and polished shape strongly suggest later human dye treatment.

Uses & applications

Used for inexpensive cabochons, beads, ornaments, and lapidary items; not generally used for construction. Value is mainly decorative and collectible rather than intrinsic.

Geological facts

Blue chalcedony can occur naturally, but saturated cobalt-blue material is commonly dyed; dye may collect around cracks, edges, or surface pits.

Field identification & locations

Identify by its waxy luster, very fine texture, lack of cleavage, and ability to scratch glass; inspect with a loupe for color pooling and test cautiously with acetone on an inconspicuous area for dye transfer. Chalcedony occurs worldwide, including Brazil, Uruguay, India, Turkey, and the United States.