Question

Excess of oxides of iron makes the brick:

(a) Red in colour

(b) Black in colour

(c) Dark blue in colour

(d) Yellow in colour

This question was posed to me in an internship interview.

I want to ask this question from Composition of Good Brick Earth topic in portion Materials for Construction of Basic Civil Engineering

Answer 1

The correct option is (c) Dark blue in colour

The explanation is: Iron oxide imparts the red colour to the brick.  Presence of magnesia makes brick yellowish and manganese makes it black.  Excess of oxides of iron makes the brick dark blue on burning.