The clay products include white wares, refractories, cement and glass. Mineral clay is the product of decomposition due to weathering of rocks or chemical action. Basically, it is composed of silica and Alnminta with other impurities like iron and manganese affecting the colour. The clay bearing much organic matter and a little iron oxide gives black, grey or brown colour. The main types of clay used as building materials are common bricks, facing bricks engineering bricks, multi-coloured and blue bricks, hollow bricks, block paving bricks, roofing and floor tiles. Clay and shades when fired, expand and bloat to produce anuses a light weight aggregate are useful bloating material in the construction industry. They are used in concrete blocks, floors and walls. Sewer pipe is manufactured by mixing fire clays and shales to obtain the desired product, having strength, chemical resistances, dimensional control etc. Fire clays are used in the large quantities in clay pipe industry, because they do not change their shape at high temperature.