What is the Definition of Pumice?

Pumice is a volcanic rock that consists of highly vesicular volcanic glass, which may or may not contain crystals. It is typically light colored. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano. The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization.

Pumice is widely used to make lightweight concrete or insulative low-density breeze blocks. When used as an additive for cement, a fine-grained version of pumice called pozzolan is mixed with lime to form a light-weight, smooth, plaster-like concrete. It is also used as an abrasive, especially in polishes, pencil erasers, cosmetic exfoliates, and the production of stone-washed jeans. "Pumice stones" are often used in beauty salons during the pedicure process to remove dry and excess skin from the bottom of the foot as well as calluses.