How are diamonds formed?
Diamond is a mineral composed strictly of the element carbon. At depths of over 100 miles, under some very specific temperature and pressure conditions, inorganic carbon forms into a solid with a specific crystalline structure, a diamond. Most diamonds found on Earth are at least one billion years old. Contrary to popular belief, diamond is not formed from metamorphosed coal. No forests or even land plants existed a billion years ago, and no coal seams have ever been found at the amazing depths necessary for diamond formation. Most diamonds have been transported to the surface via kimberlite pipes, volcanic channels that act as a conduit from the great depths of the upper mantle.
