sedimentary

Weathered gray sandstone or siltstone

Clastic siliciclastic rock, primarily quartz and feldspar grains cemented by silica or carbonate

AI-generated identification · may be incorrect

Fine- to medium-grained, gray-brown, dull to slightly earthy luster, with no obvious crystals or cleavage; likely Mohs hardness about 6–7 for quartz-rich grains, but relatively friable overall. The elongated shape appears naturally fractured and weathered.

Identified August 8, 2026More sedimentary →

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At a glance

Common name: Weathered gray sandstone or siltstone
Scientific name: Clastic siliciclastic rock, primarily quartz and feldspar grains cemented by silica or carbonate
Category: sedimentary
Identified: August 8, 2026
Method: Standard

AI Estimated Value

Typically $0–$10 as an unproven field specimen; attractive, fossil-bearing, or locality-documented pieces may sell for $10–$50.

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 when sand- or silt-sized sediment accumulated, compacted, and cemented in a river, floodplain, lake, or shallow-marine environment. Its exact geological age cannot be determined from the photograph; age depends on the local bedrock.

Uses & applications

Common sandstone is used as building stone, paving, aggregate, and occasionally decorative stone; siltstone has limited ornamental use. This irregular specimen has little commercial value unless it proves unusual or fossiliferous.

Geological facts

The pale speckles may be quartz or feldspar grains, while the darker matrix may contain clay or iron oxides. No diagnostic fossils, bedding, or mineral veins are clearly visible.

Field identification & locations

Look for gritty texture, visible sediment grains, weak layering, and scratching by a steel knife if quartz-rich; dilute acid can test for carbonate cement. Common worldwide, especially in sedimentary basins.