What is gypsum? Gypsum is usually used for interior design in the house building. Gypsum use to make up the good looking inside the house, because gypsum have smooth surface and look better after grinding with sand paper and then paint with white color. Other paint color may be applied but I still don't see other kind color applied for gypsum. Chemically Gypsum have formula CaSO4, from this formula we can see that gypsum is produced from the reaction of Ca substance with SO4 substance like sulfuric acid. By apply energy on the reaction between Calk and Sulfuric acid can produce Gypsum at the end of the reaction. The real production process my more complicated because involve many parameters on process going. On industry Gypsum can be produced especially to produce Gypsum, but in other plant Gypsum can be a side product like in Power Plant, as Gypsum is the side product on the chimney on purpose of environmental protection. The emission from power plant that much emit SO2 gas c