sedimentary

Iron-stained chert or siliceous mudstone

Microcrystalline quartz (SiO₂), likely chert with hematite/goethite staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray-brown, dull to waxy luster, very fine-grained, with reddish-brown iron-oxide veinlets or fracture coatings. No visible crystals or cleavage; irregular conchoidal-style fracture is possible.

Identified September 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed by silicification of sediment or chemical/biogenic precipitation of silica, later fractured and stained by iron-rich fluids. The photograph cannot establish a precise geological age; such rocks are common in Iranian sedimentary terrains.

Uses & applications

Used locally as aggregate, road stone, or raw material for flaking; attractive pieces may be collected, though this specimen has little commercial value.

Geological facts

The red lines are more consistent with hematite/goethite staining or healed fractures than with metallic copper minerals. Its fine texture distinguishes it from ordinary coarse sandstone.

Field identification & locations

The region near 33.5°N, 51.9°E commonly contains sedimentary rocks, chert, limestone, and iron-stained silica. Confirm with a steel-file or glass scratch test: genuine chert should scratch glass and resist a knife; dilute acid should cause no fizz unless carbonate is present.