First class bricks : (Awal Bricks) They have sharp edges, are free from cracks and other defects, and produce a clear ringing sound when struck.
2nd Quality Bricks (Lal Peti or Do number) These are comparatively less red in color and make less metallic sound when tapped against each other.
Fly-ash Bricks are a building material made from industrial waste materials, such as fly ash. Fly ash is a by-product of coal-fired power plants.
Unlike normal bricks, exposed bricks are uniform in shading and smoother in the surface.