Plaster of Paris is created by heating gypsum crystals, a soft mineral made of calcium sulphate dihydrate, to turn them into a dry powder. When it is mixed with water it reforms into a gypsum paste which is used as a building material for wall surfacing and fireproofing, or for creating sculptures and other art works. A chemical reaction occurs when the water is added to the dry plaster, in some cases reaching temperatures of up to up to 302F (150C), capable of causing serious injury. The name plaster of Paris derives from the huge gypsum deposit at Montmartre, north Paris. It was used to create some of the most important art works of the Renaissance period, including Michelangelo’s Sistine Chapel ceiling, which was painted on a thin layer of wet plaster of Paris The term putty is very popular for home decoration. It provides a very strong and durable foundation for paints and brings out the rich look. It is specially formulated for filling dents, hair cracks, levelling surface imperfections due to plaster, prevent dampness, efflorescence etc. There are various types of putty available in market. Originally only Plaster of Paris was used. Here are some basic differences between them.