Question

We know that rubbing stones produces heat.

So why it is non combustible substances? ​

Answer 1

Answer:

Explanation:

The basic concept is, when the stones are rubbed, friction takes place. The friction produces heat/sparks. but, Stone pieces are composed of small pieces of rocks and clay. So it does not have organic matter in it to burn in presence of air. Hence, it  is a non combustible.