Pumice 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). The word can be used synonymously with “volcanic ash.” It is mined from volcanic ash deposits, or it can be produced by crushing rock pumice.
About 500,000 metric tons of pumice and pumicite were mined in the United States in 2011. The total value of this pumice was about $11,200,000, or an average of about $23 per ton at the mine. The producing states were, in order of decreasing production:
 OregonNevadaIdahoArizonaCaliforniaNew MexicoKansas |