Clay is a mixture of aluminum silicate minerals such as silicic acid and natural salt, which contains silicon, aluminum, manganese, titanium, potassium, calcium and sodium. It is also rich in active biological substances, mineral salts and trace elements such as magnesium, barium, beryllium and iron. Egyptians used clay to preserve mummies, and the Romans used it during bathing. In ancient scrolls were found clay recipes for the treatment of various external or internal swelling, infections, abscesses and intestinal disorders. The average cost of clay is $35per ton.