Black sand

Another type of black sand, found on beaches near a volcano, consists of tiny fragments of basalt.

Larger waves can sort out sand grains leaving deposits of heavy minerals visible on the surface of erosion escarpments.

Purple or ruby-colored garnet sand often forms a showy surface dressing on ocean beach placers.

[1] When lava contacts water, it cools rapidly and shatters into sand and fragmented debris of various size.

A large lava flow entering an ocean may produce enough basalt fragments to build a new black sand beach almost overnight.

Black sand on a beach in Southern Iceland
Closeup of black sand from a beach in Maui, Hawaii
Black sand beach in Waianapanapa Park, Hawaii
Black sand and icebergs on a beach in Iceland
Black sands and gold in sluicebox, Blue Ribbon Mine, Alaska
Magnet for separation of black sand by hand
Black sand forming when lava hits ocean. Kīlauea volcano .