sedimentary

Sandstone Concretion

Clastic Sedimentary Rock - Quartz Arenite / Sandstone

Hardness: 6-7 (Mohs); Color: Tan, beige, or brown; Luster: Dull/Earthy; Crystal Structure: Granular/Clastic; Cleavage: None; Specific Gravity: 2.2-2.8. Features a rounded, smooth exterior with a gritty, sandy texture.

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

Identified May 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. These rounded shapes often occur in riverbeds or coastal environments where water action tumbles the stone, or as concretions forming around a nucleus within sedimentary layers.

Uses & applications

Common sandstone is used in construction as building stone, as a base for roads, and in the production of glass (if high silica). Smooth 'river rock' variants are popular in landscaping and home decor.

Geological facts

Sandstone makes up about 20% of all sedimentary rocks on Earth. Some of the world's most famous geological formations, like the Grand Canyon and Antelope Canyon, are primarily composed of various sandstone layers.

Field identification & locations

Identify in the field by its gritty texture (feels like sandpaper) and visible grains. Often found in dry washes, riverbeds, or outcrops. It will not fizz with weak acid unless it has a calcitic cement.

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