This page was created by Jim Odgers to fulfill an assignment for Gemstones and Gemology , an online course offered by Emporia State University .
Diamonds are crystals formed out of carbon.
Diamonds are formed 190 miles or more beneath the earth's surface, and rise upward through kimberlite and lamproite igneous pipes. Today it has 58 facets. Until very recently, eighty percent of the world diamond trade was controlled by DeBeers. This cartel kept the value of diamonds at a consistent level. The term carat refers to a unit of weight equivalent to 200 milligrams or 0.2 grams.