Which is the hardest material known to the world nowadays?

In terms of elements, I have heard that a form of nitride is the hardest, nearly 80 times harder than what was considered the hardest element till now, namely diamond. This form of nitride is said to be somewhat structurally akin to a diamond but differs in its composition of atoms.

In terms of materials, earlier this year a wonderful discovery of a hard material was made by scientists & reported by USA Today. As per their research, a limpet, which is a resident of the sea, has got incredibly strong teeth. This is due to it having fibers made from a mineral called goethite. Though thin, these fibres hold a lot of strength, so much so that the fibres are said to be stronger than the silk ones which a spider weaves for its webbed home. What's more, the goethite fibres can withstand even greater pressure than those uses for Kevlar vests. Just imagine the incredible possibilities of this hardest material - the structural bodies of ships and aeroplanes could incorporate it. Wow!

There are a couple of natural substances that seem to topple Diamond from its place of distinction of being the hardest material on earth.
The nitrides known as wurtzite boron nitride have the similar atomic structure as the diamond, but their atoms are little different.
Another interesting discovery has brought up new dimension to the concept of hardest material. The teeth of a limpet are found to have a super strong structure of fibres which have been adjudged being the strongest of all. It has been observed that they are stronger than silk. Scientists are considering the possibilities of mimicking the structure found in these teeth in manufacturing the material that can be much helpful in structural engineering.