Mortar
clay
Depends on the size of the bricks.
this depends on the size of the bricks. Assuming 4x9 inch bricks then 3.14 x (15/2)2 x 1212 = 25434 sq inches 1 brick is 4 x 9 = 36 sq in. 25434 / 36 = 706.5 bricks but there would be some waste from cutting the bricks to make a circle.
They both have the same mass. A kilogram measure mass regardless of the material, volume etc.
Mud
Bricks. Tons and tons of bricks.
Fire bricks are made of ceramic materials and have a low thermal conductivity
Mud Bricks
Bricks are made by pressing clay into a brick shape then leaving it to dry in the sun
sun-dried mud or clay
Usually ceramics such as calcium silicate. If you mean the "traditional" material, that would be adobe.
The material used to make ancient Greek homes was mud bricks that needed repair very often
Mortar
Clay is a raw material for making bricks and pottery.
Mortar is what is used to stick bricks together.
Bricks