Calcium sulfate gypsum is a natural hydrate and is found in several crystalline forms that are found in the Earth’s solid crust reserves in the form of relatively thick crusts. This material is extracted from the earth’s crust and is used to produce powder plaster. About 160 to 200 million years ago, when the seas dried up, layers of gypsum formed on the seabed. Gypsum is one of the oldest building materials used in the world, which has been produced by traditional methods in the past centuries and has been used differently compared to the present time. After extraction from the mine, gypsum is taken to a furnace like lime and heated to a temperature of about 180 degrees Celsius to lose some of its crystalline water molecules and become a gypsum form that can be used as a building material and a suitable material for molding. Gypsum is usually powdered with special mills and then it is packed in suitable bags and be prepared for sale. The particle size of high quality gypsum powder should be less than 0.15 mm. In most cases, a combination of gypsum and pure water is used for various applications. However, if needed, adding some different materials can reduce the hardening time. For example, by adding 1% salt to a mixture of gypsum and water, the setting time is reduced and if the salt content is more than 4%, the setting time is increased. For example, by adding 1% salt to a mixture of gypsum and water, the setting time is reduced and if the salt content is more than 4%, the setting time is increased. Gypsum is naturally white in color and may appear gray, bluish gray, pink, or yellow due to the presence of impurities in materials such as clay and iron oxide. In fact, the purity of gypsum is defined based on the percentage of gypsum mineral in it. According to the American Society for Testing and Materials (ASTM), the minimum purity required for gypsum in industrial materials is 70% gypsum, while most gypsum being traded is 75% to 90% pure.