The taking place between outdated volcanic rocks, the cavities are usually full of deposits of secondary minerals launched by percolating water. The glass by itself kinds threads, fibres, and thin partitions between the vesicles. Rhyolite and trachyte pumices are white, andesite pumices often yellow or brown, and pumiceous basalts (such https://edenproductsltd.co.uk/2025/04/17/the-history-of-pumice-stone-from-ancient-civilisations-to-modern-day-uses/