White-burning clays (used in whiteware)
a. Kaolin:
i. Residual
ii. Sedimentary
b. Ball clays
B. Refractory clays (having a fusion point above 1600C but not necessarily white
burning)
a. Kaolin (sedimentary)
b. Fire clays:
i. Flint
ii. Plastic
c. High alumina clays:
i. Gibbsite
ii. Diaspore
C. Heavy clay-products clays (of low plasticity but containing fluxes)
a. Paving brick clays and shales
b. Sewer-pipe clays and shales
c. Brick and hollow tile clays and shales
D. Stoneware clays (plastic, containing fluxes)
E. Brick clays (Plastic, containing iron oxide)
a. Terra-cotta clays
b. Face and common brick
F. Slip clays (containing more iron oxide)