Brunette Girl On The Beach With Black Sand

Lava fragments
Lava, erupting onto a shallow sea floor or flowing into the sea from land, may cool so rapidly that it shatters into sand and rubble. The result is the production of huge amounts of fragmental volcanic debris. The famous "black sand" beaches of Hawaii, such as Punaluu Black Sand Beach, were created virtually instantaneously by the violent interaction between hot lava and sea water.