Technical Specification Of The Ordinary Gypsum
( Hemihydrate Gypsum CaSO4 H2O )

Colour: White
Grain Fineness: Residue Not More Than 6% By Weight On Sieve 9.2 mm Mesh.
Setting Time Initial Setting Time: 5-9 Min. Final Setting Time: 15-20 Min
Bending Strength: After 7 Days Not Less Than 40Kg/Cm2
Compressive Strength: After 7 Days Not Less Than 55Kg/Cm2
Hemi hydrate Calcium Sulphate: Not Less Than 75% By Weight.
Calcium Carbonate: From 9% - 13% By Weight.
Sodium Chloride: Not More Than 1% By Weight.
Iron % Aluminium Oxide: Not More Than 2% By Weight.
Silica Oxide: Not More Than 3% By Weight.
Combined Water: From 3% - 6% By Weight.

Remark :-
This is the technical specification for National Gypsum Company for all plants (Riyadh Yanbou Dammam).