Question

which is the hardest subtance diamond or platinum

Answer 1

Diamond is the hardest naturally occurring substance found on Earth. But it is not the hardest substance. Wurtzite boron nitride (synthetic) andlonsdaleite (which comes from meteorites) are both harder.

Answer 2

Diamond is the hardest naturally occurring substance on the earth

It is an allotropic form of carbon.

It is non electrolyte means it can't conduct electricity.

It is rigid due to its compact structure.

In diamond every carbon atom is connected to four other carbon atoms.

Means it has no free electrons.

So your answer is

Diamonds is harder than platinum