sedimentary

Weathered iron-rich sandstone or siltstone

Clastic siliciclastic sedimentary rock, likely ferruginous sandstone/siltstone (quartz-rich, Fe-oxide cement)

AI-generated identification · may be incorrect

Tan to reddish-brown, dull earthy luster, very fine to fine-grained, rounded weathered surface with cavities and possible bedding or fracture lines. Estimated hardness 5–7 if sandstone, or about 3–5 if unusually clay-rich; no visible crystals or cleavage.

Identified August 29, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich sandstone or siltstone
Scientific name: Clastic siliciclastic sedimentary rock, likely ferruginous sandstone/siltstone (quartz-rich, Fe-oxide cement)
Category: sedimentary
Identified: August 29, 2026
Method: Standard

AI Estimated Value

Typically $0–$10 as an ordinary specimen; up to about $15–$30 if locality-confirmed or unusually attractive.

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

Formed from compacted and cemented sand or silt, later stained by oxidized iron minerals such as hematite or goethite. Exact age cannot be determined from the photograph; ferruginous sedimentary rocks are common in the Arizona volcanic-and-sedimentary terrain near 33.5°N, 110.8°W.

Uses & applications

Usually collected as a local geological specimen; sandstone can be used for building stone, paving, and aggregate, though this small weathered piece has little commercial value.

Geological facts

The elongated grooves may reflect bedding, weathering along fractures, or impressions from softer mineral-rich layers rather than crystal structure.

Field identification & locations

A hand lens should reveal sand grains; rubbing it on unglazed porcelain may leave a reddish streak if iron-rich. A dilute hydrochloric-acid test can detect carbonate cement, while a steel nail helps distinguish softer claystone from harder sandstone. Common regional alternatives include volcanic tuff, altered andesite, and iron-stained quartzite.