mineral

Tumbled milky chalcedony (likely common opal or quartz-rich chalcedony)

Chalcedony, microcrystalline SiO₂; identification is uncertain from the photo

AI-generated identification · may be incorrect

Pale gray-white, opaque to slightly translucent, with a smooth tumbled surface and waxy luster; quartz hardness about 6.5–7 Mohs, trigonal crystal structure at the microscopic level, no obvious cleavage. Brown patches may be iron-oxide staining or inclusions.

Identified October 11, 2026More mineral →

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At a glance

Common name: Tumbled milky chalcedony (likely common opal or quartz-rich chalcedony)
Scientific name: Chalcedony, microcrystalline SiO₂; identification is uncertain from the photo
Category: mineral
Identified: October 11, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a small common tumbled pebble; higher value would require distinctive patterning, provenance, or confirmed gem 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

Silica-rich fluids deposited the material in rock cavities or fractures; its exact geological age and source cannot be determined from the image.

Uses & applications

Commonly tumbled for collecting, craft, and jewelry; chalcedony is also used for beads and ornamental objects.

Geological facts

Chalcedony is made of extremely fine quartz crystals, so individual crystals are generally not visible without magnification.

Field identification & locations

Look for waxy luster, hardness near 7, and conchoidal fracture; a scratch or acid test is not advisable on a collectible. Chalcedony occurs worldwide in volcanic cavities and sedimentary deposits; the photo does not establish a locality.