metamorphic

Quartz-rich breccia (likely silicified fault breccia)

Silica-cemented polymictic breccia; primarily quartz (SiO₂) with possible feldspar, mica, and mafic rock fragments

AI-generated identification · may be incorrect

Angular to subangular dark and pale clasts are cemented by translucent white-tan quartz or chalcedony. Quartz hardness is 7, with vitreous to waxy luster, no cleavage, conchoidal fracture, and specific gravity near 2.65; the specimen may be naturally weathered or polished.

Identified September 11, 2026More metamorphic →

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At a glance

Common name: Quartz-rich breccia (likely silicified fault breccia)
Scientific name: Silica-cemented polymictic breccia; primarily quartz (SiO₂) with possible feldspar, mica, and mafic rock fragments
Category: metamorphic
Identified: September 11, 2026
Method: Standard

AI Estimated Value

About $5-$30 as a common specimen; $30-$100+ if unusually attractive, 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

Probably formed when fractured rock fragments accumulated in a fault or hydrothermal breccia zone and were cemented by silica-rich fluids. Its exact age cannot be determined from the photograph; age depends on the host region and may range from Precambrian to much younger.

Uses & applications

Used mainly as a decorative or collector stone; attractive pieces may be cut or polished for cabochons and ornaments, but it has little bulk industrial value.

Geological facts

The contrasting angular fragments and light silica veins are characteristic of brecciation followed by mineral-rich fluid circulation.

Field identification & locations

Look for sharp clasts, pale quartz/chalcedony cement, and a hard scratch-resistant surface; common in hydrothermal veins and fault zones worldwide. A locality label or tests for hardness and acid reaction are needed for precise identification.