Question

Why is petroleum called black gold?

Answer 1

Petroleum is considered to be as costly as the gold.That's why it got it's name as "Black gold".Black is due to it's colour.

Answer 2

Petroleum is also known as Black Gold - because when crude oil is extracted from the land it is black in color. People call it gold because of its oils and value . It is very difficult to find. So it is called Black Gold.