Cement
It is made up of limestone by crushing it into powder and modifying its some properties.
Strength of the cement mainly depends on the quality of lime stone quarry. Blackish limestones have better properties than whitish limestone. It does not mean a faint color cement lack in strength properties but darker color always performs well on strength properties.
Clay or shale so called, are generally “Bentonite” and “Laterite” mix with Limestone to form a clinkers.
There % in mix is around...