Sandstone (with ripple marks)

Physical Properties

Hardness: 6-7 on Mohs scale; Color: Grey-brown to tan; Luster: Dull/Earthy; Crystal Structure: Clastic (granular texture); Cleavage: None; Specific Gravity: 2.2-2.8

Formation & Geological History

Formed from the accumulation and cementation of sand-sized mineral grains or rock fragments. These specifically show ripple marks formed by ancient water currents or wind, typically from Paleozoic to Cenozoic eras.

Uses & Applications

Commonly used in construction for paving, building facades, and as an abrasive. Fine specimens with ripple marks are prized by educational collectors for demonstrating sedimentary processes.

Geological Facts

Ripple marks on sandstone are 'sedimentary structures' that can tell geologists the direction and speed of ancient water currents or tides from millions of years ago.

Field Identification & Locations

Identify by its gritty, abrasive feel (like sandpaper) and visible layering or ripple crests. Found in basin environments, ancient beaches, and deserts worldwide.

Identified on: 4/20/2026

Mode: Standard