The transpiring among the outdated volcanic rocks, the cavities usually are crammed with deposits of secondary minerals released by percolating drinking water.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