sedimentary

Sandstone

Arenite (primarily SiO2)

Hardness: 6-7 Mohs; Color: Tan, beige, brown; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific gravity: 2.2-2.8

Hardness: 6-7 Mohs
Color: Tan, beige, brown
Luster: Dull/Earthy

Identified April 15, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, beige, brown; Luster: Dull/Earthy; Crystal structure: Clastic (granular); Cleavage: None; Specific gravity: 2.2-2.8

Formation & geological history

Formed through the accumulation and cementation of sand-sized mineral grains or rock fragments (usually quartz). This specimen is a water-worn river pebble, likely shaped over thousands of years by fluvial erosion.

Uses & applications

Used widely in construction as a building material, for paving stones, and historically in glass making if high in silica content.

Geological facts

Sandstone makes up about 10-20% of Earth's sedimentary rock. It is a major reservoir for water (aquifers) and oil/gas due to its porosity.

Field identification & locations

Identify by its gritty, sandpaper-like feel and visible grains. Commonly found in riverbeds, beaches, and desert environments. It will not fizz with acid unless it has a calcitic cement.