mineral

Brown chalcedony (likely jasper or petrified wood fragment)

Microcrystalline quartz, SiO₂; brown coloration likely from iron oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; waxy to glassy luster, opaque to translucent brown-gold coloration, and no visible cleavage. The rounded, glossy surface suggests natural water wear or polishing; internal banding or wood texture is not clearly visible.

Identified August 26, 2026More mineral →

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At a glance

Common name: Brown chalcedony (likely jasper or petrified wood fragment)
Scientific name: Microcrystalline quartz, SiO₂; brown coloration likely from iron oxides
Category: mineral
Identified: August 26, 2026
Method: Standard

AI Estimated Value

Approximately $2–$15 for a small common rough piece; $20–$100+ if it proves to be patterned petrified wood or attractive lapidary material.

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 or replaces organic material, with iron staining producing brown tones; such material commonly formed in volcanic or sedimentary settings over millions of years.

Uses & applications

Used as lapidary rough, cabochons, beads, carvings, and decorative stone; quality depends on pattern, translucency, and polish.

Geological facts

Chalcedony is a fibrous variety of quartz composed of intergrown microscopic crystals. If the specimen shows cellular grain or growth rings under magnification, it may instead be silicified wood.

Field identification & locations

Common in Brazil, Uruguay, Mexico, the western United States, Madagascar, and Australia. A glassy surface, quartz-like hardness, and inability to scratch it with a steel knife support chalcedony; acid produces no reaction.