sedimentary

Weathered sandstone or iron-stained mudstone

Clastic sedimentary rock; likely quartz-rich sandstone, possibly ferruginous siltstone

AI-generated identification · may be incorrect

Brown to olive-tan, dull earthy luster, very fine to medium clastic texture, rounded weathered surface, and no obvious crystals or cleavage. Likely Mohs hardness about 5–7 if sandstone, with moderate specific gravity around 2.3–2.7; the image cannot confirm grain size or cement.

Identified September 3, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when sand or silt accumulated, compacted, and cemented in an ancient river, coastal, lake, or floodplain environment; iron oxidation produced the brown coloration. Its geological age cannot be determined from the photograph.

Uses & applications

Common sandstone is used for building stone, paving, aggregate, and landscaping; attractive pieces may be collected, but this specimen appears chiefly of educational or decorative value.

Geological facts

The smooth shape likely reflects prolonged water, soil, or wind weathering rather than deliberate manufacture. Iron-bearing cement can create mottled red-brown and olive coloration.

Field identification & locations

Look for visible quartz grains, bedding, lamination, or a gritty fracture; sandstone scratches glass, whereas softer mudstone generally does not. Common worldwide, especially in sedimentary basins; acid testing is usually negative unless carbonate cement is present.