It is found in abundance in the sun, stars, comets, and atmospheres of most planets. Graphite is one of the softest known materials while diamond is one of the hardest. Carbon, as microscopic diamonds, is found in some meteorites. Diamonds are also recovered from the ocean floor off the Cape of Good Hope. This new form of carbon is the subject of great interest in research laboratories today.
Carbon is present as carbon dioxide in the atmosphere and dissolved in all natural waters.
Coal, petroleum, and natural gas are chiefly hydrocarbons. Carbon is unique among the elements in the vast number of variety of compounds it can form. While silicon might take the place of carbon in forming a host of related compounds, it is not possible currently to form stable compounds with very long chains of silicon atoms. Strange Matter cartoon included by kind permission of Nick Kim at the University of Waikato , New Zealand. Here is a brief summary of the isolation of carbon.