sedimentary

Iron-stained dark pebble (likely chert or iron-rich sedimentary rock)

Indeterminate; possibly microcrystalline quartz (SiO₂) with iron-oxide staining

AI-generated identification · may be incorrect

Dark gray-brown, fine-grained, and water-worn, with ochre patches likely iron oxides; hardness and exact luster cannot be confirmed from the image. If chert, hardness is about 7 Mohs and fracture is typically conchoidal.

Identified September 28, 2026More sedimentary →

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At a glance

Common name: Iron-stained dark pebble (likely chert or iron-rich sedimentary rock)
Scientific name: Indeterminate; possibly microcrystalline quartz (SiO₂) with iron-oxide staining
Category: sedimentary
Identified: September 28, 2026
Method: Standard

AI Estimated Value

About $0–$5 as an ordinary pebble; higher value would require distinctive features or confirmed identification.

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

Could be a rounded fragment of chert or another fine-grained rock, later stained by iron-bearing fluids and smoothed by stream or beach transport. Age and formation setting cannot be determined visually.

Uses & applications

This small specimen is mainly suitable for collecting or display; chert can be used for tools, and iron-rich rocks may be sources of iron ore when sufficiently concentrated.

Geological facts

The rusty yellow-brown areas are consistent with iron oxides such as goethite or limonite, but visual identification is not definitive.

Field identification & locations

A hard scratch on glass and a sharp, curved fracture would support chert; a steel nail should not readily scratch it. Exact identification would require testing hardness, streak, and density.