mineral

Botryoidal chalcedony (possibly jaspery agate)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining and possible calcite/aragonite inclusions

AI-generated identification · may be incorrect

White, cream, tan, and rusty-brown specimen with rounded botryoidal surfaces and locally drusy texture; typically waxy to vitreous luster, cryptocrystalline structure, no obvious cleavage, Mohs hardness about 6.5–7, and specific gravity near 2.6.…

Identified August 16, 2026More mineral →

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At a glance

Common name: Botryoidal chalcedony (possibly jaspery agate)
Scientific name: Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining and possible calcite/aragonite inclusions
Category: mineral
Identified: August 16, 2026
Method: Standard

AI Estimated Value

About $10–$40 as a common display specimen; $50–$150 if unusually attractive, translucent, or locality-documented.

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 precipitates in cavities, fractures, or porous volcanic/carbonate rock, commonly in successive botryoidal layers; iron oxides create the brown staining. Exact age and locality cannot be determined from the photograph.

Uses & applications

Used as lapidary rough, cabochons, carvings, decorative specimens, and occasionally ornamental stone; this irregular piece has modest commercial value.

Geological facts

Botryoidal means grape-like; each rounded knob can represent a silica growth surface around a cavity or nucleus.

Field identification & locations

Look for waxy translucent edges, conchoidal fracture, very fine texture, and hardness sufficient to scratch ordinary glass. Common sources include Brazil, Uruguay, Mexico, India, and the western United States; acid testing can help detect abundant carbonate but may damage the specimen.