What is the purpose of a pumice stone?

could someone please tell me what a pumice stone does..

it takes off dead skin from areas like knees elbows and the bottom of your foot.

Pumice is widely used to make lightweight concrete or insulative low-density 'breeze-block' type bricks. When used as an additive for cement, a fine-grained version of pumice called pozzolan is mixed with lime to form a light-weight, smooth, plaster-like concrete. This form of concrete was used as far back as Roman times.

It is also used as an abrasive, especially in polishes, cosmetics exfoliants, and for stone-washed jeans. "Pumice stones" are often used in salons during the pedicure process to remove dry and excess skin from the bottom of the foot as well as calluses. Finely ground pumice is added to some toothpastes and heavy-duty hand cleaners as a mild abrasive. Perhaps the most famous product advertised to contain pumice is Lava soap. It is a heavy-duty hand soap, sold in both bar and liquid form, for mechanics and others who get very dirty hands.

that funny because today me an my friend were having a heated arguement on what the usage of pumice is
I was correct
It is used as an abrasive, especially in polishes, cosmetics exfoliants, and for stone-washed jeans. "Pumice stones" are often used in salons during the pedicure process to remove dry and excess skin from the bottom of the foot as well as calluses. Finely ground pumice is added to some toothpastes and heavy-duty hand cleaners as a mild abrasive.

I USE IT TO CLEAN HARD WATER STAINS ON TOILETS. I HAVE WELL WATER AND IT STAINS REALLY BAD. GOOD LUCK

Agree with all the above - but watch out you don't rub too hard on the skin on your feet - you can take off a living layer of skin and that hurts the next day!