Natural black diamonds extremely rare. SuperJeweler sells only heat treated black diamonds, treated with the High Pressure Heat Treatment (HPHT) method. In HPHT treatment, white included poor quality diamonds are heated to approximately 1260 degrees Fahrenheit, in a reducing atmosphere, meaning under the conditions of very little oxygen, and the unpleasant white and included diamonds become black. HPHT treatment is completely safe, and produces gem quality black diamonds.
