The occurring among outdated volcanic rocks, the cavities tend to be stuffed with deposits of secondary minerals launched by percolating water. The glass by itself types threads, fibres, and skinny partitions concerning the vesicles. Rhyolite and trachyte pumices are white, andesite pumices usually yellow or brown, and pumiceous basalts (which https://edenproductsltd.co.uk/2025/04/17/the-history-of-pumice-stone-from-ancient-civilisations-to-modern-day-uses/