sedimentary

Likely sandstone

Quartz-rich sandstone (indeterminate variety)

AI-generated identification · may be incorrect

Tan-gray, dull to slightly earthy luster, visibly granular and poorly sorted, with dark mineral or lithic grains. Typical hardness is about 6–7 for quartz grains, but the cement may scratch more easily; no reliable cleavage is visible.

Identified September 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Sandstone forms when sand-sized sediment—commonly quartz and feldspar—is compacted and cemented in rivers, deserts, or shallow-marine settings. The image cannot establish its geological age; sandstones are widespread in Iran, including central Iranian sedimentary basins.

Uses & applications

Used as building and paving stone, aggregate, and occasionally decorative stone. This ordinary, unpolished fragment has little commercial or collector value.

Geological facts

The dark streaks may be iron/manganese staining, mica, or lithic fragments; a close inspection of a fresh surface is needed to distinguish these. The specimen is consistent with regional sedimentary geology near 33.5°N, 51.9°E.

Field identification & locations

Look for sand-sized grains, bedding, and gritty texture; quartz-rich sandstone commonly scratches glass, though cement affects the result. A dilute hydrochloric-acid test can reveal carbonate cement by fizzing, but avoid testing valuable specimens and use proper safety precautions.