Where do diamonds come from?

All diamonds are formed inside volcanoes.
   They are formed under immense heat and pressure below the earth and are exported to the surface during volcanic eruptions. Diamonds are moulded underground at a distance of about 100 - 300miles (160 - 480 km) within. They are mostly found inside the volcanic rock Kimberlite, and mined where volcanic activity is still regular. The others are found exposed due to being washed out of their original Kimberlite.
  There are only twenty places in the world that produce diamonds across the globe. Russia is the leading producer of diamonds, following are Botswana, The Democratic Republic of Congo, Australia and the desecrated South Africa.
   Diamonds are pure carbon, so is graphite (the thing that the 'lead' in pencils are made of), but the carbon atoms are arranged differently.
  Diamond is the hardest naturally occurring substance in the world, and was once the hardest material known to man. That was, of course until August of 2005, when German scientists managed to concoct a harder material in their labs. This material was made by compressing and heating super - strong carbon molecules at 2,226 degrees centigrade and was called Aggregated Carbon Nanorods (ACNR).

   The largest Diamond known to man is 2,500 miles (4,000 km) wide and measures ten billion trillion trillion carats.The diamond sits inside the star White Dwarf BPM 37093, (nicknamed 'Lucy' from The Beatles song 'Lucy in the sky with diamonds') which is 8 lightyears above Australia, located in the Constellation Centaurus.