Description
Pumice is a volcanic ash which is formed when lava is permeated with gas bubbles during the solidification process. Pumice is very fragile and breaks apart quite easily into small particles. Pumice is the softest abrasive media in use today.
Uses
Included in soap, pumice gives it a light abrasive quality which easily removes almost any grease or grime imaginable and because it is a natural mineral, it isn't toxic 10 people or the environment. For commercial applications, pumice has become the most widely used grit in many manufacturing processes which require a mild abrasive characteristic.
Source: http://www.australianperlite.com/pumice/