Diamonds and Graphite are both made from Carbon Atoms. Why is Graphite so much weaker?
Graphite, mineral form of carbon. Carbon is Allotropic (That is, it exists in more than one form); other forms include Diamond and buckminsterfullurene. Although, graphite is chemically the same as Diamond, it differs greatly from that mineral in most of its physical properties. Graphite is black, opaque, and metallic in luster and has a density of 2.09 to 2.2g/cubic centimeter. Graphite is extremely soft- its hardness rates 1 to 2 or a scale of 1 to 10. It smudges anything with which it comes in contact; it feels greasy or slippery to the touch. It crystallizes in flakes or large irregular masses rather than well-developed crystals. A good conductor of electricity, graphite is a poor conductor of heat. It occurs in nature as a mineral that invariably contains impurities.
Graphite is widely distributed over the world; important deposits are found in China, India, North Korea, Mexico, Brazil, the Czech Republic, and Turkey. Graphite is made artificially by baking a mixture of petroleum coke and coal tar pitch at 950 Degree C (174 Degree F) for 11 to 13 weeks, then transferring the baked product to electric graphitizing furnaces and heating it to about 2800 degree C (5,600 Degree F) for 4 or 5 weeks. Most of the graphitizing takes place because of the temperature, but the process is also a refining step, as virtually al the metal oxide impurities in the raw carbon are reduced to metal and vaporized. Source: “Graphite” Microsoft Encarta 2006 (DVD). Redmond, WA: Microsoft Corporation, 2005.