pumice

Definition

A light, porous type of pyroclastic igneous rock, formed during explosive volcanic eruptions when liquid lava is ejected into water or air as a froth containing masses of gas bubbles, which are frozen into the rock as the lava solidifies.

Etymology

From Anglo-Norman and Old French pomis (“pumice stone”), from Latin pūmex (“pumice stone”). Doublet of pounce.

Example Sentences

• "The wind blew close to the ground - it rooted among the tussock grass - slithered along the road, so that the white pumice dust swirled in our faces - settled and sifted over us and was like a dry-skin itching for growth on our bodies."