Some of the essential qualities of bricks are as follows:

a. The bricks should be table moulded, well burnt in kilns, copper coloured, free from cracks and with sharp and square edges. The colour should be uniform and straight.

b. The bricks should be uniform shape and should be of standard size.

c. The bricks give a clear metallic ringing sound when struck with each other.

d. The bricks when broken or fractured should show a bright homogenous and uniform compact structure free from voids.

e. The bricks should not absorb water more than 20% by weight for first class bricks and 22% by weight for second class bricks, when soaked in water for a period of 24hrs.

f. The bricks should be sufficiently hard. No impressions should be left on brick surface, when it is scratched with finger nail.

g. The bricks should not break into pieces when dropped flat on hard ground from a height of about 1 metre.

h. The bricks should have low thermal conductivity and they should be sound proof.

i. The bricks, when soaked in water for 24hrs, should not show deposits of white salts when allowed to dry in shade.

j. No bricks should have crushing strength less than 5.50N/mm2.