Brick

Brick, building material made of clay, sometimes reinforced with straw, shaped into rectangles and hardened by heat. Sun-dried bricks were used as a building material at least 6,000 years ago in Mesopotamia. The discovery of the technique of firing clay in kilns enabled hard durable bricks to be made. Examples of fired bricks have been found in excavations at the city of Ur that are at least 5,000 years old. The Greeks used bricks, and the Romans made an art of brick masonry in their large-scale constructions. After the fall of Rome, bricks were not used again on a large scale until the 12th and 13th centuries.

Although bricks are important in the construction industry, concrete, plastics, and light alloys have taken over some of their functions. Modern bricks include: common brick, used for ordinary building purposes; face brick, used to resist erosion or for decoration; firebrick (refractory brick), which can withstand the high temperatures found in furnaces and kilns; paving brick, larger, harder, and more water-resistant than the common brick; and insulating brick, a porous type that insulates against extremes of temperature.