mineral

Polished white-and-brown chalcedony (likely agate/jasper)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining or jasperous inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; white to cream with rusty brown patches, waxy-to-glassy luster, cryptocrystalline quartz structure, and no obvious cleavage. The smoothly polished surface indicates a shaped or tumbled specimen.

Identified September 15, 2026More mineral →

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At a glance

Common name: Polished white-and-brown chalcedony (likely agate/jasper)
Scientific name: Microcrystalline quartz, SiO₂; chalcedony with iron-oxide staining or jasperous inclusions
Category: mineral
Identified: September 15, 2026
Method: Standard

AI Estimated Value

Approximately $5–$25 for a small polished piece; exceptional patterns, provenance, or craftsmanship may bring $30–$100.

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 and fractures in volcanic rock, with iron oxides producing the brown coloration; commonly Cenozoic to older, depending on the host deposit. Exact age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, carvings, beads, ornaments, and lapidary material; durable but not generally high-value gemstone material.

Geological facts

Agate and jasper overlap texturally: agate is typically more translucent and banded, while jasper is opaque and mottled. The specimen appears predominantly opaque, so jasper or jasper-rich chalcedony is plausible.

Field identification & locations

Identify by its fine texture, quartz-like hardness, lack of cleavage, and resistance to scratching by steel; glass can help test hardness, though polished surfaces make testing undesirable. Common sources include Brazil, Uruguay, India, Madagascar, Mexico, and the western United States.