mineral

Botryoidal chalcedony (agate/geode fragment)

Chalcedony, microcrystalline SiO₂; likely quartz with minor iron-oxide and carbonate inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent gray-brown to honey color, waxy to vitreous luster, cryptocrystalline quartz, no cleavage, specific gravity about 2.6. Rounded botryoidal growths and druzy crystalline patches are visible.

Identified August 22, 2026More mineral →

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At a glance

Common name: Botryoidal chalcedony (agate/geode fragment)
Scientific name: Chalcedony, microcrystalline SiO₂; likely quartz with minor iron-oxide and carbonate inclusions
Category: mineral
Identified: August 22, 2026
Method: Standard

AI Estimated Value

About $10–$40 for a common hand specimen; $50–$150 or more if unusually attractive, large, well-crystallized, 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 fills cavities, fractures, or vesicles in volcanic rock and precipitates in successive layers; iron impurities create the brown coloration. The specimen’s precise geological age and locality cannot be determined from the image.

Uses & applications

Used as a lapidary and ornamental stone, in carvings, cabochons, polished specimens, and occasionally industrial silica products.

Geological facts

Botryoidal texture means grape-like rounded surfaces produced by radiating microscopic quartz fibers; later cavities may develop sparkling druzy quartz.

Field identification & locations

Identify it by its waxy translucence, conchoidal fracture, rounded layered texture, and hardness sufficient to scratch ordinary glass; common sources include Brazil, Uruguay, Mexico, India, and the western United States.