sedimentary

Tumbled dark pebble, likely iron-rich jasper or chert

Jasper/chert, predominantly microcrystalline quartz (SiO₂) with iron-oxide impurities

AI-generated identification · may be incorrect

Opaque dark reddish-brown, smoothly waterworn or tumbled, with dull to faint waxy luster and no visible crystals or cleavage. Quartz hardness is about 6.5–7 Mohs; relatively dense, approximately 2.6 g/cm³.

Identified August 8, 2026More sedimentary →

Explore Tumbled dark pebble, likely iron-rich jasper or chert in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Tumbled dark pebble, likely iron-rich jasper or chert
Scientific name: Jasper/chert, predominantly microcrystalline quartz (SiO₂) with iron-oxide impurities
Category: sedimentary
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $1–$10 as a common tumbled or found pebble; higher values require distinctive patterning, provenance, or lapidary quality.

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

Likely formed as silica-rich sediment that became microcrystalline quartz and was colored by iron oxides, then rounded by stream transport or tumbling. Exact age and locality cannot be determined from the image.

Uses & applications

Commonly used for cabochons, beads, carvings, polished stones, and decorative aggregate; this small unverified piece has little commercial value.

Geological facts

Jasper and chert can look similar; jasper is generally opaque and impurity-rich, while chert is often more uniformly gray, brown, or translucent at thin edges.

Field identification & locations

Field clues include a glassy or waxy fracture, lack of cleavage, and inability to scratch it with a steel knife; it should scratch ordinary glass. Common sources include sedimentary formations and river gravels worldwide.