Geology topics
Robert Crangle
Publications and source records attributed to Robert Crangle.
Mineral resource of the month: Pumice and pumicite
Pumice is an extrusive igneous volcanic rock formed through the rapid cooling of air-pocketed lava, which results in a low-density, high-porosity rock. Fine-grained pumice, or pumicite, is defined as minute grains, flakes, threads or shards of volcanic glass, with a size finer than 4 millimeters.
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