The strongest allotrope of carbon, the diamond, is an optically isotropic crystal that has its comprising carbon atoms bound to each other in a cubic lattice pattern. This pattern involves the bonding of each carbon atom to four neighboring carbon atoms via strong covalent bonds. The strong bonds between each atom of the crystal renders it extremely hard and strong. It is the hardest known substance to man, presently. But the property of hardness does not imply that it is indestructible. Just because a substance is harder than another, does not imply that it cannot be destroyed. For example, glass (natural or toughened) is considerable harder than steel, yet, a bar of steel can easily break the glass. On heating, glass melts faster than steel, and can be eroded (by chemicals) faster as well. Similarly, a diamond is not indestructible. The fact that diamonds are cut and shaped to be used as jewelry indicates that, it is possible to shatter or break the crystal under the right conditions. Under normal conditions of atmospheric temperature and pressure, a diamond retains all its physical and chemicals properties, since the covalent bonds between the carbon atoms require an immensely high amount of energy to be broken. Therefore, if a high-enough temperature and pressure environment is provided, along with suitable catalysts, it is possible to change the physical and/or chemical nature of a diamond. Hence, contrary to popular belief, diamonds are not really indestructible. But it must also be noted that, these pure carbon crystals can only be destroyed in the presence of extremely high temperature and pressure.