The term can be utilized synonymously with "volcanic ash." It is actually mined from volcanic ash deposits, or it could be made by crushing rock pumice. Rub the pumice stone in circular motions above the calloused location. Use Mild, round motions to slough away the useless pores and skin like https://edenproductsltd.co.uk/2025/04/17/the-history-of-pumice-stone-from-ancient-civilisations-to-modern-day-uses/