Our pumice stones come from the only canadian volcano (Mount Meager) which is located in British Columbia.
These are extremely porous volcanic stones whose low-density allows them to float. The pumice stone is formed when a temperature of 500 to 600 degrees Celsius is reached. The expulsed lava cools very quickly and the drop in pressure causes an outgassing that creates bubbles, hence the stone's porosity and low density. They are composed of rhyolite, dacite or andesite fragments.
Pumice stone has been in use since Roman times and is suitable for use on the hands, elbows, soles of feet and heels.
Gently massage rough skin and calluses with stone for several minutes in the bath or shower. Use a little soap or bath gel to reduce friction.