The taking place between previous volcanic rocks, the cavities usually are stuffed with deposits of secondary minerals released by percolating drinking water. The glass itself forms threads, fibres, and slender partitions concerning the vesicles. Rhyolite and trachyte pumices are white, andesite pumices frequently 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/