Volcanic Stone
This page is the CodyCross answer for the clue below from La Bella Roma, Group 415, Puzzle 5 (Italian Renaissance).
Question is: Volcanic Stone
and the answer is: PUMICE
Word Meaning:
PUMICE — 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.
Definitions from Wiktionary.