Diamond, the hardest substance known to man, and a precious mineral, is obtained from nature. Diamond is not an average substance. Their extreme hardness, resistance to tarnishing, exquisite clarity and clean facelting make them all above the rest of minerals. Diamonds demonstrate distinctive properties of which you may not be aware: e. g, Diamonds are excellent conductors of heat, but poor conductors of electricity. The heat conductivity of diamond is so extraordinary that modern tests to determine whether a gem is genuine diamond or fake, is based on measurement of the gem’s heat conductivity. 

Diamonds play another important role in modern industrial society: an industrial workhorse. The unusual properties of diamond makes it technologically very important. Because of its extreme hardness, diamonds are excellent for surgical cutting tools and coatings on cutting tools for drilling, mining, and industrial productions. A rapidly emerging technology centers on thin films of diamond. Diamond films have been marketed on tweeters in stereo speakers and as scratchproof coatings on watches. Diamond coated windows for infra-red scanning systems and light filtering masks are also on the market. Diamonds offer promise for new electronic materials.  

Diamond is pure natural carbon with atoms organized in close packed cubic arrangement that gives the stones their extreme hardness. Under normal conditions, graphite is the most stable form of carbon, because the bonds in graphite are stronger. In part this stability can be attributed to resonance. Having the double bond character spread evenly throughout the entire structure adds extra stability to graphite. When several different forms of matter with the same compositions exist, the most stable structure is called the thermodynamically favourable form. Under the usual conditions of atmospheric pressure and room temperature, the most stable or thermodynamically favourable form of carbon is graphite.  

However, at high pressure, diamond becomes more stable than graphite. We can understand why the preferred arrangement of atoms may change with pressure. On average the carbon atoms in diamond are closer together than the carbon atoms in graphite. As a result diamonds are more dense (that is, more mass in a given volume) than graphite. When a piece of graphite is subjected to high pressure, the external forces compress the graphite or push the carbon atoms closer together. Under these conditions it is more favourable for the carbon atoms to rearrange themselves into diamond structure. If graphite is squished (very high pressure is applied) then the graphite will be transformed into diamond. 

Diamonds are formed deep inside the earths interior where crushing pressure and blistering heat work together for a long period of time to create the diamond lattice. Although scientists have puzzled long about how diamonds are transported to earth’s surface, a recent discovery of diamonds in Canada may have shed some light on this issue. Scientists now believe that, narrow volcanic pipes running down into the earths interior allows diamonds to be transported via violent eruptions to the earth’s surface. The eruptions were so fast and so violent that diamonds were coughed straight to the surface. It is believed the time taken to form a natural diamond is approximately billions of years. 

Synthetic diamonds on the other side can be formed in much the same way as natural diamonds. Graphite is heated to temperatures exceeding 15000C at about 60,000 atmospheres of pressure (that is a pressure 60,000 times greater than the normal pressure exerted by our atmosphere). Even at these temperatures and pressures, diamond formation is not easy. Addition of small amounts of the metallic elements, iron or nickel speeds up the reaction. Why are the metals added? The role of the metallic additives is to reduce the amount of energy needed to form diamond from graphite.

 The metal in reaction with the lower activation energy acts as a catalyst in the reaction. A catalyst is a substance that affects the rate of a reaction without being consumed by the overall reaction process. Chemistry says that, catalysts do not affect the thermodynamics of the reaction; rather they affect the kinetics. In diamond formation, the metal catalysts are trapped in the diamond lattice as it is formed. This is why many synthetic diamonds are coloured, while naturally occurring diamonds, which lack in impurities are colourless. So, natural diamonds are free of any impurities compared to synthetic diamonds, and hence costly and more durable.