Talc is an aqueous magnesium silicate, and its theoretical formula is 3 MgO 4SIO2 H2O. It contains 63.5% SiO2, 31.7% MgO and 4.8% H2O in its ideal composition. It is white, greenish-transparent, slippery, massive, and soft. Its hardness varies between 1-1.5 according to the MOHS scale. Its density is between 2.6-2.8 gr/cm3. Talc is fire resistant. It hardens and solidifies when heated at high temperatures. It does not degrade with acids.