It is also used in old phonograph needles. Heated to 1800 o C, diamond transforms to graphite . At room temperatures and pressures, graphite is the most stable allotrope of carbon. It is soft, black, slippery and much less dense than diamond . The carbon atoms in graphite are arranged in layers, thus, giving graphite the ability to conduct electricity within the layer.
Layers easily slide over each other.
This soccer-ball shaped molecule has potential applications in electronics, catalysis, polymers, and medicines. It occurs in the crust of the earth mainly in coal and petroleum and in the form of calcium carbonate , or magnesium carbonate rocks. Marble, limestone, chalk, coral are found in enormous deposits throughout the world. Many of these compounds are remnants of fossilized marine organisms. At the same time, by similar reactions with sulfuric and nitric acids from acid rain , limestones which protect lakebeds are destroyed.