Pumice Stone Formation near Vilaflor, Tenerife, Canary Islands, Spain

View of Sunset Crater Volcano from the east slope of the Lenox Crater Trail, the dark gray soil is volcanic pumice, Arizona, United States of America, North America

Pumice stone field, Teide National Park, UNESCO World Heritage Site, Tenerife, Canary Islands, Spain, Europe

Mount St. Helens After Eruption

Caldera volcano with pumice fields, yellow coloured sulphur stones, Alexandros crater, Nisyros, Dodecanese, Greece, Europe

Eastern edge of Mount Hood volcano and Elliot Glacier, Cooper Spur Trail, Cascade Range, Oregon, USA

A backpacker crosses the exotic landscape of the ash and pumice-covered Valley of Ten Thousand Smokes in Katmai National Park, with Mt. Katmai (left), Trident Volcano (right), and the Knife Creek Glaciers looming in the distance; Alaska, United States of

Mt. Griggs rises over the ash- and pumice-covered Valley of Ten Thousand Smokes in Katmai National Park. The ash-covered Knife Creek Glaciers can be seen coming out of the valley at right; Alaska, United States of America

The colorful landscape of the Valley of Ten Thousand Smokes and Baked Mountain in Katmai National Park; Alaska, United States of America

The eastern peak of Trident Volcano rises above the ash-covered Knife Creek Glaciers at sunset in Katmai National Park; Alaska, United States of America

Mt. Griggs rises above the ash- and pumice-covered Valley of Ten Thousand Smokes in Katmai National Park; Alaska, United States of America

Trident Volcano rises above the ash-covered Knife Creek Glaciers at sunset in Katmai National Park; Alaska, United States of America

Close-up of hands using pumice stone on foot