摘要 : Pumice is an extrusive igneous volcanic rock formed through the cooling of air-pocketed lava, which results in a highly porous, low-density rock. A small percentage of pumice was used in abrasive-type products, including pencil er... 展开 Pumice is an extrusive igneous volcanic rock formed through the cooling of air-pocketed lava, which results in a highly porous, low-density rock. A small percentage of pumice was used in abrasive-type products, including pencil erasers, a pohshing agent for circuit boards and television monitors, an exfoliant in cosmetics, and a variety of heavy-duty hand cleaners. 收起