<Li> <P> Illustrates the porous nature in detail . </P> </Li> <P> Illustrates the porous nature in detail . </P> <Li> <P> Rocks from the Bishop tuff, uncompressed with pumice on left; compressed with fiamme on right . </P> </Li> <P> Rocks from the Bishop tuff, uncompressed with pumice on left; compressed with fiamme on right . </P>

Pumice is the only rock that floats in water