Clay bricks are made by mixing clay and other materials with water to make them pliable, shaping the mixture into the desired form and heating it in a kiln. Brick making is a very ancient vocation, although the basic process of mixing, shaping, and heating remains the same.
Clay bricks are not entirely made out of clay; they often include coarser-grained ingredients to reduce shrinkage and cracking when they are placed in the kiln. Sand and shale are two very common additives.
Water is added to the clay mixture, which makes it soft enough to shape. There are different shaping methods, ranging in sophistication from simply sculpting the bricks into blocks by hand to extruding bricks from large industrial machines.
Once the mixture has attained its proper shape, it is heated in a kiln to make it hard and durable. Kiln temperatures are usually in excess of 2,000 degrees Fahrenheit. The heat from the kiln also contributes to the bricks' final color.