Ventifact

A ventifact (also wind-faceted stone, windkanter[1]) is a rock that has been abraded, pitted, etched, grooved, or polished by wind-driven sand or ice crystals.

These geomorphic features are most typically found in arid environments where there is little vegetation to interfere with aeolian particle transport, where there are frequently strong winds, and where there is a steady but not overwhelming supply of sand.

Ventifacts can be abraded to eye-catching natural sculptures such as the main features of the White Desert National Park near Farafra Oasis in Egypt.

Individual stones, such as those forming desert pavement, are often found with grooved, etched, or polished surfaces where these same wind-driven processes have slowly worn away the rock.

Ventifacts have also been discovered on Mars, where such sharp immobile rocks have caused significant damage to the wheels of the Curiosity rover.