Pumice

Hardness of 6 on the Mohs scale, highly vesicular, white to gray or yellowish color, dull to earthy luster, and low density allowing it to float on water.

Formed during explosive volcanic eruptions when gas-rich felsic lava rapidly cools and depressurizes, trapping gas bubbles within the glassy matrix.

Widely used in lightweight construction aggregates, abrasive personal care products, horticultural soil amendments, and stone-washing textiles.

Pumice is one of the few natural rocks that can float on water due to its extreme porosity and trapped gas bubbles.

Easily identified by its extremely low weight-to-size ratio and frothy, sponge-like texture filled with tiny vesicles. Found worldwide near active or ancient tectonic plate subduction zones and volcanic arcs.