where do pumice stones originate
The vesicles are actually gas bubbles that were trapped in the rock during the rapid cooling of a gas-rich frothy magma. The material cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure. Thus, pumice is an amorphous volcanic glass known as a  mineraloid .umice is produced in two forms: rock pumice and pumicite. Pumicite is a name given to very fine grained pumice (less than 4 millimeters in diameter down to submillimeter sizes).