Question

What is the use of corundum?

(a) Used as an abrasive

(b) Used as precious gemstones

(c) Used as Construction materials

(d) Used as abrasive and precious gemstones

The question was posed to me during an interview.

The origin of the question is Formation and Descriptive Study of Minerals in section The Study of Minerals of Engineering Geology

Answer 1

Right answer is (d) Used as abrasive and precious gemstones

The explanation: Corundum is used as both abrasive and also as precious gemstones. The former is due its high hardness of about 9 and the latter is due its appearance, and the names of some common semi-precious gemstones are ruby, emerald, sapphire etc.