Our pumice is a near-white, milled volcanic glass that has many uses in fine arts. Add pumice to paint to make it appear mat when dried, to add texture and to increase body without tinting the color. Pumice can also be added to grounds to give it "tooth" and as an abrasive to smooth and polish substrates and grounds.This grade of white pumice is used to polish surfaces such as wood, and added to chalk and gesso grounds to give it tooth. This grade of pumice is white so it will not discolor grounds. Use this grade to add fine texture to paint and to give it a matt appearance.Pumice is formed when lava from an erupting volcano flows onto the earth's surface and cools. The comparatively low atmospheric pressure at the surface results in the sudden release of steam and other dissolved gases from the still molten mass, thereby producing bubbles. This creates the pocked appearance familiar in "lava rock" used for gas grill briquettes and landscape rock. Pumice deposits are only found within a few miles of ancient volcanoes.Our pumice is from a deposit located in Espanola, New Mexico. The ore is mined from open pits and then transported to the plant where it is crushed, milled and dried. It is then processed through a modern classification system to produce a rigorously controlled and consistently uniform product.