sedimentary

Weathered brown rock, likely iron-stained sandstone or chert

Indeterminate; probable quartz-rich sandstone/chert with iron-oxide staining

AI-generated identification · may be incorrect

Opaque brown, dull to slightly earthy luster, irregular rounded shape, and no visible crystals or cleavage. Likely hardness about 6–7 Mohs if quartz-rich; specific gravity roughly 2.4–2.7, though photography cannot confirm texture or composition.

Identified August 12, 2026More sedimentary →

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At a glance

Common name: Weathered brown rock, likely iron-stained sandstone or chert
Scientific name: Indeterminate; probable quartz-rich sandstone/chert with iron-oxide staining
Category: sedimentary
Identified: August 12, 2026
Method: Standard

AI Estimated Value

$0–$5 as an ordinary fragment; potentially $5–$20 if unusually attractive, collectible, or confirmed as quality jasper/chert.

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 a naturally weathered sedimentary fragment formed from compacted quartz sand or microcrystalline silica, later stained by iron oxides during oxidation. Age and exact formation environment cannot be determined from the image.

Uses & applications

Common pieces have little commercial value; sandstone is used for building stone and aggregate, while chert is used for tools, aggregate, and occasionally lapidary work.

Geological facts

The rusty brown color commonly comes from hematite or goethite coatings and cement. A glass-scratching test can distinguish quartz-rich material from softer mudstone, but should be performed cautiously.

Field identification & locations

Look for gritty sand grains and visible layering for sandstone; a smooth, waxy surface and conchoidal fracture suggest chert. Commonly found in sedimentary terrains, stream gravels, and weathered outcrops worldwide.