Finding the rough diamonds is only the first step. Once diamonds have been mined and processed out of the 'overburden' (that is, the kimberlite rocks in which they are imbedded), the rough crystals are sorted and categorized according to their size, color, shape and other characteristics. At this point, a diamond can follow one of two routes. 1.Diamond Trading Corporation (DTC) 2.Central Selling Organization (CSO). I know this much of information lets know more from others.