mineral

Tumbled blue chalcedony (likely blue quartz/chalcedony)

Cryptocrystalline silica, SiO₂; likely chalcedony, possibly dyed or surface-coated

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, vitreous to waxy luster, translucent blue-gray color, and no visible cleavage; cryptocrystalline quartz has a specific gravity near 2.60. The rounded shape and uneven surface indicate tumbling or natural abrasion.

Identified August 11, 2026More mineral →

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At a glance

Common name: Tumbled blue chalcedony (likely blue quartz/chalcedony)
Scientific name: Cryptocrystalline silica, SiO₂; likely chalcedony, possibly dyed or surface-coated
Category: mineral
Identified: August 11, 2026
Method: Standard

AI Estimated Value

$2–$15 for a small common tumbled piece; $20–$100+ for attractive natural color, unusual patterns, or quality lapidary material.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Chalcedony forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, often during the Cenozoic or older geological periods. Blue coloration may result from microscopic inclusions, while vivid electric blue commonly indicates treatment.

Uses & applications

Used as a lapidary stone for cabochons, beads, carvings, and inexpensive jewelry; also collected as a decorative specimen. Common material generally has modest commercial value.

Geological facts

Chalcedony is a microcrystalline aggregate of quartz and moganite rather than a single large-crystal mineral. The image alone cannot reliably distinguish natural blue chalcedony from dyed quartz or glass.

Field identification & locations

Common sources include Brazil, Uruguay, India, Madagascar, Turkey, and the western United States. Check for dye concentration in cracks, bubbles or conchoidal fracture suggesting glass, and scratch resistance against steel or glass; avoid destructive testing on valuable pieces.