'''Pumice''' is a light-colored, frothy volcanic rock, usually of [[dacite]] or [[rhyolite]] composition, formed by the expansion of gas in erupting [[lava]]. Commonly perceived as lumps or fragments of pea size and larger but can also occur abundantly as ash-size particles.<ref name="vulcan">[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology (Foxworthy and Hill, 1982)]</ref> | '''Pumice''' is a light-colored, frothy volcanic rock, usually of [[dacite]] or [[rhyolite]] composition, formed by the expansion of gas in erupting [[lava]]. Commonly perceived as lumps or fragments of pea size and larger but can also occur abundantly as ash-size particles.<ref name="vulcan">[http://vulcan.wr.usgs.gov/Glossary/volcano_terminology.html Glossary of Volcano and Related Terminology (Foxworthy and Hill, 1982)]</ref> |