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.
The 'hardness' of a mineral is generally determined by the Mohs scale and is defined as the scratch resistance of a mineral. Diamonds are the hardest minerals known to man, but what is the hardest metal? That honor goes to chromium, a metal perhaps best known as the key ingredient in stainless steel. Chromium is also commonly used in chrome plating, which acts as a form of protection against corrosion and physical damage.