sedimentary

Quartz-rich sandstone or quartzite cobble

Quartz arenite; possibly weakly metamorphosed quartzite (SiO₂-dominant)

AI-generated identification · may be incorrect

Light tan-gray, fine-grained, dull to slightly sugary luster, with rounded cobble shape and weathered surface. Quartz has Mohs hardness 7; sandstone commonly scratches glass only variably, while quartzite is harder and more resistant; cleavage is absent.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely lithified quartz sand cemented by silica, iron oxides, or carbonate; if metamorphosed, recrystallization produced quartzite. Exact geological age and locality cannot be determined from the photograph.

Uses & applications

Common sandstone is used for building stone, paving, aggregate, and abrasives; quartzite is used for durable countertops, flooring, crushed stone, and ornamental specimens. This unexceptional cobble has little jewelry value.

Geological facts

The granular texture and pale color suggest quartz-rich material, but the image does not clearly resolve individual grains or bedding. A streak, acid, hardness, and broken-surface examination would separate sandstone from quartzite.

Field identification & locations

Common in river gravels, beaches, glacial deposits, and exposed sandstone or quartzite terrains. Look for visible sand grains and possible cement in sandstone; fused interlocking grains and conchoidal fracture favor quartzite.