mineral

Botryoidal chalcedony/geode fragment

Microcrystalline quartz (SiO₂), likely chalcedony with druzy quartz; exact identification requires testing

AI-generated identification · may be incorrect

Typically white to cream with translucent, rounded botryoidal surfaces and sugary/vitreous druzy luster; quartz hardness is 7 Mohs, no cleavage, conchoidal fracture, and specific gravity about 2.60–2.65. The image may also show minor iron-oxide staining and host-rock inclusions.

Identified August 25, 2026More mineral →

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At a glance

Common name: Botryoidal chalcedony/geode fragment
Scientific name: Microcrystalline quartz (SiO₂), likely chalcedony with druzy quartz; exact identification requires testing
Category: mineral
Identified: August 25, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a small common fragment; $30–$150+ for unusually attractive, well-crystallized or locality-labeled specimens.

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 groundwater deposited quartz and chalcedony in cavities, commonly in volcanic rock; formation may range from Cenozoic to older depending on locality. The specimen appears naturally weathered or broken from a cavity lining.

Uses & applications

Used as a decorative stone, lapidary material, and mineral-collection specimen; attractive pieces may be cut or polished for display and jewelry.

Geological facts

Botryoidal means the surface formed as overlapping rounded growths. Chalcedony and quartz can coexist, with chalcedony forming earlier and coarse druzy quartz crystallizing later.

Field identification & locations

Look for curved botryoidal growth, translucent edges, waxy-to-glassy luster, and hardness sufficient to scratch ordinary glass; vinegar will not fizz. Common sources include Brazil, Uruguay, Mexico, Morocco, India, and the western United States.