The most suitable of gypsum rock minerals found in nature is gypsum. As gypsum can easily be dehydrated under heat effect (looses water in its crystals), gypsum is economical and advantageous.

Although stated in many sources that obtaining gypsum powder from gypsum rock by heating fine grinded mineral under 120-160 centigrade degrees, but in real life it is NOT true. To produce High Quality gypsum powder many instruments should be used together in fine coordination.

Theoretically; Gypsum powder is obtained by CaSO4.2H2O + heat <—> CaSO4.1/2 H2O + 3/2 H2O reaction.

This rection is reversable, and when it is treated with water can absorb 3/2 of water that it lost and becomes hardened.

As it had been mentioned above, although its theoretically expressed like this, matters that determine quality of gypsum production are instruments like temperature, vacuum, speed, time and etc must be studied well and running of them synchronously of them based on experience.

These instruments if not used correctly phase balance of gypsum is changed, quality of gypsum will be degraded towards anhydrite (gypsum without water), bonding structure of gypsum weakens, strength and adherence decrease and when applied to a wall there appears cracks and molders.