sedimentary

Sandstone (Weathered Cobble)

Clastic sedimentary rock (primarily SiO2)

Hardness: 6-7 on Mohs scale (due to quartz content); Color: Tan, beige, grey, with traces of green lichen; Luster: Dull/Earthy; Crystal Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8

Hardness: 6-7 on Mohs scale (due to quartz content)
Color: Tan, beige, grey, with traces of green lichen
Luster: Dull/Earthy

Identified March 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments. This specific specimen is a 'glacial cobble' or river rock, rounded by mechanical weathering and transport over thousands of years.

Uses & applications

Commonly used in construction as aggregate, for paving, or as decorative garden stones. High-purity sandstone is used in glass manufacturing.

Geological facts

Sandstone makes up about 20-25% of all sedimentary rocks on Earth. This specific rock shows signs of biological weathering on its surface, indicated by the small green patches of lichen growth.

Field identification & locations

Identify in the field by its gritty, sandpaper-like texture and visible grain structure. This specimen is a common 'erratic' or river-worn cobble found throughout temperate regions in Northern North America and Europe.

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