sedimentary

Weathered sandstone or quartz-rich metamorphic rock

Likely feldspathic sandstone (lithic arenite); exact identification requires testing

AI-generated identification · may be incorrect

Tan-brown, dull to slightly silky, fine- to medium-grained and rounded; likely Mohs 5–7 depending on cement and quartz content. No obvious crystals or cleavage; visible granular texture and irregular fracture suggest quartz-rich material.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Most likely lithified sand deposited in a river, beach, dune, or shallow-marine environment, then cemented by silica, iron oxides, or clay. Its geological age cannot be determined from the photograph.

Uses & applications

Common sandstone is used as building stone, paving, aggregate, and decorative material; attractive pieces may be collected, but this specimen appears ordinary and unpolished.

Geological facts

The rusty tan coloration commonly comes from iron-oxide coatings on quartz and feldspar grains. A glass-scratch test and dilute hydrochloric-acid test can help distinguish quartz-rich sandstone from calcareous sandstone.

Field identification & locations

Common worldwide, especially in sedimentary basins; likely sandstone if it feels gritty and shows visible sand grains, whereas a smooth crystalline fracture may indicate quartzite. Test hardness, grain texture, and acid reaction before naming it definitively.