If you tend to mouth breathe at night, it is important to make a check for the dryness every morning. While night sleeping, it is very important to breathe through your nose. In case you neglect your mouth breathing for 7-8 hours every night, it will be difficult for you to change your breathing on a permanent basis.
Diamond is currently thought to be the hardest natural material on Earth, having a hardness of ten out of ten on the Mohs scale of mineral hardness. Diamond is made up of carbon atoms which share strong covalent bonds (where electrons are shared between atoms) and are equally spaced in a lattice arrangement.
A diamond ring. Scientists have calculated that wurtzite boron nitride and lonsdaleite (hexagonal diamond) both have greater indentation strengths than diamond. Source: English Wikipedia. (PhysOrg.com) -- Currently, diamond is regarded to be the hardest known material in the world. But by considering large compressive pressures under indenters, scientists have calculated that a material called wurtzite boron nitride (w-BN) has a greater indentation strength than diamond.