sedimentary

Quartz-rich breccia or silicified breccia

Cryptocrystalline quartz/chalcedony (SiO₂) with iron oxides and dark lithic fragments; exact classification is uncertain from the photograph

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, white to brown/gray, vitreous to waxy luster, and no obvious cleavage; the angular dark fragments cemented by translucent silica suggest brecciation. The brown coloration likely reflects iron-oxide staining.

Identified September 11, 2026More sedimentary →

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At a glance

Common name: Quartz-rich breccia or silicified breccia
Scientific name: Cryptocrystalline quartz/chalcedony (SiO₂) with iron oxides and dark lithic fragments; exact classification is uncertain from the photograph
Category: sedimentary
Identified: September 11, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$100+ if unusually attractive, well polished, or locality-documented.

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 fractured rock fragments are cemented by silica-rich fluids, commonly in hydrothermal veins or silicified fault zones; age depends on its host formation and cannot be determined visually. It may also represent strongly silicified volcanic or sedimentary rock.

Uses & applications

Primarily a collector or lapidary specimen; attractive pieces may be polished for display, cabochons, or ornamental stone, but it has little bulk construction value.

Geological facts

The specimen appears partly polished or naturally weathered, with botryoidal/translucent chalcedonic areas and darker mineral-rich fragments. Acid testing is usually negative unless carbonate remains in the matrix.

Field identification & locations

Look for angular clasts, translucent quartz/chalcedony, glassy fracture, and hardness sufficient to scratch ordinary glass; a streak, hardness test, and thin-section or chemical analysis would refine identification. Common in hydrothermal districts and silicified volcanic terrains worldwide.