Verified Answer :

Graceanne11

Diamond. It can only be cut with another diamond.

Answer: Option (c) is the correct answer.

Explanation:

Moh's scale is used to detect the harness of a mineral. This scale displays harness of 10 minerals.

According to Moh's scale, the hardness of minerals given in the option are as follows:

  • Topaz = 8
  • Talc = 1
  • Diamond = 10

Graphite is not included in Moh's scale.

Thus, we can conclude that the hardest known mineral is diamond.