We all know that diamond is the hardest known natural material existing in nature, exponentially harder than corundum. It is also the least compressible and most stiffest substance. It also has an exceptional thermal conductivity about four times more than that of copper and an extremely low thermal expansion, chemically inert when compared to most of the acids and alkalis, a diamond is transparent from far infrared through the deep ultraviolet, and is one of the few materials with negative electron affinity.



Due to its negative electron affinity it can easily repels water, but readily accepts hydrocarbons. Diamond is not a good conductor of electricity so it does not conduct electricity well, although some of them may be semiconductors. If subjected to very high temperature in the presence of oxygen, a diamond could easily burn itself. Having a high specific gravity, a diamond is amazingly dense due to the low atomic weight of carbon. High dispersion and high refractive index gives a diamond its high reflectance. Diamond as a gemstone is most commonly clear or pale blue, but colored fancies are found in all the colors of the rainbow. Elements like boron and nitrogen add the beauty to its appearance by giving it impurities.

Although found in volcanic rocks like kimberlite and lamproite, diamond crystals may contain inclusion of other minerals like chromite or garnet. Due to these impurities certain diamonds may show a blue fluoresce whereas others may show violet or yellow. These quantities of impurities found in a diamond usually does classify the diamond type. The most common type of a natural diamond may contain 0.3% nitrogen as impurity. Very few natural diamonds would contain 0.1% impurity and type Ib may contain up to 500 ppm nitrogen as impurity. Industrial diamonds are also produced by the process of High Pressure High Temperature synthesis in which a graphite and a metallic catalyst are placed in hydraulic press under high temperature and pressure conditions. Such diamonds are usually used for industrial purposes such as in cutting tools or drill-bits.

No matter what shape size or color, the mere mention of the word diamond would fill our mind with multitude of concepts and images. The king of gems is something superb that glitters, dazzles, and symbolizes purity, love and strength. The gem of 75th wedding anniversary, is also a commitment for a never ending love story. Diamond is immortal, indomitable, exotic that is formed in the earth's interior and shot to the surface by a few extraordinary volcanoes. Probably three billion years in age, a diamond is the oldest thing a man would like to own. Diamond is a beautiful shape, marking its presence by its glitters and dazzling shine. It is also a high tech super material for our technological society. But it also rests in a beautiful wedding ring to mark another never ending love story with strength and purity.