What is the softest rock on earth?

Talc is the softest known natural mineral. It is given the designation of 1 on the Mohs hardness scale, which gauges the relative hardness of a substance, usually an unknown mineral. The hardest known natural mineral is diamond, which is designated 10 on the Mohs hardness scale.

Talc is an important ingredient in many products, such as cosmetics, rubber, ceramics and paints. It is also used in industrial products that include pesticides and lubricants. While talc is the softest mineral, it is actually very heavy; it is as dense or denser than marble. Soapstone, which was commonly used as material for statues, is an extremely dense, talc-based mineral.