mineral

Polished chalcedony (likely moss/plume agate)

Microcrystalline quartz, SiO₂; chalcedony with possible iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent white to gray with pink, tan, and rusty-yellow internal patches. Waxy to vitreous luster, cryptocrystalline structure, no cleavage, conchoidal fracture; polishing produces a glossy surface.

Identified September 15, 2026More mineral →

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At a glance

Common name: Polished chalcedony (likely moss/plume agate)
Scientific name: Microcrystalline quartz, SiO₂; chalcedony with possible iron-oxide inclusions
Category: mineral
Identified: September 15, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a small polished cabochon or palm stone; $30–$100+ for unusually attractive patterns, translucency, or provenance.

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

Forms when silica-rich groundwater fills cavities and fractures in volcanic rock, later depositing layered chalcedony and iron-oxide inclusions. Usually Cenozoic to older, with exact age dependent on locality.

Uses & applications

Commonly cut and polished into cabochons, worry stones, beads, and decorative objects; generally modest jewelry and collecting value.

Geological facts

The cloudy body and dendritic or plume-like inclusions suggest agate rather than ordinary quartz, but the image alone cannot confirm the exact variety or locality.

Field identification & locations

Identify by its smooth waxy appearance, translucent edges, very high polish, lack of cleavage, and inability to scratch with a steel knife; quartz or feldspar may scratch it. Common sources include Brazil, Uruguay, Madagascar, India, Mexico, and the western United States.