mineral

Tumbled honey-brown chalcedony or agate

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

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent honey-yellow to brown, waxy-to-glassy luster, cryptocrystalline structure, and no visible cleavage. The smooth shape indicates tumbling or water wear.

Identified August 11, 2026More mineral →

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At a glance

Common name: Tumbled honey-brown chalcedony or agate
Scientific name: Microcrystalline quartz (SiO₂), likely chalcedony; exact identification requires testing
Category: mineral
Identified: August 11, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small common tumbled piece; $20–$100+ if it proves to be unusually attractive banded agate or a confirmed rare variety.

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

Hardness about 6.5–7 Mohs; translucent honey-yellow to brown, waxy-to-glassy luster, cryptocrystalline structure, and no visible cleavage. The smooth shape indicates tumbling or water wear.

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, precipitating microcrystalline quartz; commonly Cenozoic to older, depending on host rock and locality.

Uses & applications

Used for cabochons, beads, carvings, and small decorative specimens; durable but generally modestly valuable unless strongly colored or patterned.

Geological facts

Chalcedony and agate are varieties of quartz; agate typically shows distinct banding, which is not clearly visible in this specimen.

Field identification & locations

Common in volcanic terrains, river gravels, and silica-rich cavities worldwide, especially Brazil, Uruguay, India, Madagascar, and the western United States. A scratch test, translucency, and absence of cleavage help distinguish it from calcite or glass.