Here's why:

* Minerals are naturally occurring, solid, inorganic substances with a specific chemical composition and crystal structure. Examples include quartz, feldspar, and calcite.

* Rocks are aggregates of one or more minerals. Pumice is made up of various minerals, primarily silica, but also contains aluminum, iron, magnesium, calcium, and sodium oxides.

Pumice is formed from volcanic eruptions. The rapid cooling and expansion of molten rock (lava) creates the porous, lightweight structure that makes it unique.