Terracotta is a kind of earthenware which is generally used as a substitute for stone in the ornamental parts of buildings. It is made like clay products burnt at very high temperature; usually contains : 8 parts sifted dry clay, 3 parts crushed pottery, 2 parts white sand, I part ground glass. Porous terracotta is made by adding saw dust or ground cork, and is very light but weak structurally. It can be sawed and nailed very easily.
Terracotta is vitrified on the surface and made into various colours and patrons. Hollow blocks are made for walling etc. It is fire-proof and is unaffected by the atmosphere and can be jointed with cement mortar.