Singing sand, also called whistling sand, barking sand or singing dune, is sand that produces sound. The sound emission may be caused by wind passing over dunes or by walking on the sand.
Singing sand dune in Altyn-Emel National Park, Almaty Province, Kazakhstan
Sand blowing off a crest in the Kelso Dunes of the Mojave Desert, California
Sand dunes on the edge of Dunhuang
Singing sand from Gold Coast, Queensland, Australia under microscope
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.
Sand dunes in the Idehan Ubari, Libya
Depiction of sands: glass, dune, quartz, volcanic, biogenic coral, pink coral, volcanic, garnet, olivine. Samples are from the Gobi Desert, Estonia, Hawaii and the mainland United States. (1×1 cm each)
Heavy minerals (dark) in a quartz beach sand (Chennai, India)
Sand from Coral Pink Sand Dunes State Park, Utah. These are grains of quartz with a hematite coating providing the orange color.