sedimentary

Tumbled brown stone, likely jasper or iron-rich chert

Microcrystalline quartz (SiO₂), possibly iron-oxide-bearing jasper/chert

AI-generated identification · may be incorrect

Opaque brown, weakly to moderately lustrous, smoothly tumbled with no visible cleavage; quartz hardness about 6.5–7 Mohs and specific gravity about 2.6. The image is insufficient to distinguish jasper from chert or another iron-rich stone confidently.

Identified August 17, 2026More sedimentary →

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At a glance

Common name: Tumbled brown stone, likely jasper or iron-rich chert
Scientific name: Microcrystalline quartz (SiO₂), possibly iron-oxide-bearing jasper/chert
Category: sedimentary
Identified: August 17, 2026
Method: Standard

AI Estimated Value

Usually $1–$10 for a small common tumbled stone; approximately $10–$30 if unusually patterned, locality-specific, or sold as a quality cabochon.

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

Likely formed from silica-rich sediment that lithified and recrystallized into microcrystalline quartz, with iron oxides producing the brown color; age depends on source deposit and cannot be determined visually.

Uses & applications

Used as inexpensive lapidary material for tumbled stones, cabochons, beads, and decorative objects; not typically used as an architectural stone in this small form.

Geological facts

Jasper and chert are varieties of cryptocrystalline quartz whose individual crystals are too small to see unaided. A glass-scratch test can help confirm quartz hardness, though it may damage the specimen.

Field identification & locations

Commonly found in sedimentary formations, river gravels, and volcanic-associated silica deposits worldwide. A strong reaction to a magnet would suggest unusually abundant iron minerals rather than ordinary jasper.