type(A) type(B) type(C)

sio2 67 73 63-67
al2o3 30-1 19-21 28-30
fe2o3 0.2 0.8 0.1 - 0.5
tio2 - 0.3 0.2
cao 0.2 0.56 0.7
mgo 0.4 0.3 - 0.7 0.9 -1
k2o 0.7 2 - 3.1 4.5 - 5
na2o 0.5 0.5 - 1 0.9 - 1.2
so3 0.01 - -

color white to cream white to gray white to cream

fired strenght 150 380 500
(kg/cm2)

dry strenght 25 8 17.