sedimentary

Tumbled polymict breccia (probable quartz-rich breccia)

Clastic breccia composed mainly of quartz, feldspar, and iron-oxide-stained rock fragments

AI-generated identification · may be incorrect

Hardness is approximately 6–7 Mohs; mottled cream, gray, brown, and reddish colors with a dull to slightly vitreous luster. Angular-to-subangular fragments are cemented in a fine matrix; cleavage is absent as a whole, and specific gravity is roughly 2.6–2.8.

Identified August 10, 2026More sedimentary →

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At a glance

Common name: Tumbled polymict breccia (probable quartz-rich breccia)
Scientific name: Clastic breccia composed mainly of quartz, feldspar, and iron-oxide-stained rock fragments
Category: sedimentary
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $3–$15 for a common tumbled specimen; roughly $20–$75 for an attractive polished or provenance-specific piece.

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 broken rock fragments accumulate and become cemented by silica, calcite, or iron oxides, commonly in fault zones, volcanic settings, or alluvial fans. Its precise age cannot be determined from the photograph and depends on the source formation.

Uses & applications

Used as a decorative tumbled stone, lapidary material, aggregate, and occasionally as facing stone; generally unsuitable for fine jewelry unless it polishes attractively.

Geological facts

The angular fragment pattern distinguishes breccia from conglomerate, whose clasts are rounded. Red-brown coloration commonly results from hematite or limonite staining.

Field identification & locations

Look for sharply bounded clasts of differing colors and textures in a cemented matrix; a streak, acid test, and magnification would help identify the cement and minerals. Breccias occur worldwide, especially near faults and volcanic terrains.