This video lecture from Group IIIA and Group IVA Elements (F.Sc. second year Chemistry) covers the silicates of aluminum, magnesium and calcium. Feldspar changes into kaolin in the earth’s crust which is commonly called soft clay. It contains alumina and silica and is either hydrated or anhydrous giving hardness to the clay. Magnesium silicate is also called talc and finds use in several powders. Calcium magnesium silicate is also called asbestos. Find more e-learning material and educational video lectures in Urdu at maktab.pk. These videos are free to use for promotional and commercial purpose by keeping the credits to Maktab.