Buddha; Mathura, Uttar Pradesh, India; 200–300 CE; Sandstone; 30.5 x 33 x 12.7 cm. Asian Art Museum, San Francisco, and Google Arts & Culture

Porous sedimentary rock formed from compressed silicate grains, found in many regions across the world and varying widely in colour. Sandstone has been used since prehistory for a variety of purposes, including construction and sculpture.