sedimentary

Polished jasper pebble (likely brecciated or spiderweb jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and silica vein networks

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; reddish-brown body with cream-white web-like veins, opaque, waxy to dull luster, and no obvious cleavage. Compact microcrystalline quartz has a specific gravity near 2.6.

Identified September 5, 2026More sedimentary →

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At a glance

Common name: Polished jasper pebble (likely brecciated or spiderweb jasper)
Scientific name: Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and silica vein networks
Category: sedimentary
Identified: September 5, 2026
Method: Standard

AI Estimated Value

About $3–$20 for a common polished pebble; $20–$75 for an unusually attractive, large, or well-patterned 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

Hardness about 6.5–7 Mohs; reddish-brown body with cream-white web-like veins, opaque, waxy to dull luster, and no obvious cleavage. Compact microcrystalline quartz has a specific gravity near 2.6.

Formation & geological history

Formed when silica-rich fluids replaced or cemented sedimentary/volcanic material, with iron oxides producing the brown-red color and later fractures filled by pale silica or calcite. The exact geological age cannot be determined from the image.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and decorative objects; it has little industrial value compared with ordinary quartz aggregate.

Geological facts

The pattern is characteristic of brecciated or spiderweb-style jasper, but visual identification cannot distinguish jasper from some veined chert or quartzite with certainty.

Field identification & locations

Identify by its opaque appearance, very fine grain, hardness, and resistance to scratching by a steel knife; it commonly occurs as waterworn stream, beach, or glacial pebbles in silica-rich terrains. Avoid testing polished specimens destructively.