sedimentary

Sandstone (Fluvial Pebble)

Arenite

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

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

Identified July 4, 2026More sedimentary →

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Physical properties

Hardness: 6-7 Mohs; Color: Tan, beige, light 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, typically silicate minerals like quartz. This specific rounded shape indicates transport and erosion in a riverbed or high-energy water environment over thousands of years.

Uses & applications

Used primarily as construction aggregate, road base, and in some decorative landscaping applications. Larger deposits are vital as aquifers and petroleum reservoirs.

Geological facts

Sandstone makes up about 10-20% of Earth's sedimentary rocks. Its characteristic layering can record ancient environmental cycles like tides or floods.

Field identification & locations

Identify by its gritty texture (feels like sandpaper) and visible grains. Common in riverbeds, canyons, and coastal outcrops. Collectors often look for unique erosion patterns or internal banding.