Author: Simic D., Zaitsev A. M., 2012.
The color of diamonds can be changed by HPHT (High Pressure High Temperature) process. Any type of diamond can be treated and depending on their chemistry they can be turned to vivid yellows, pinks, reds, oranges and greens, and type IIa to colorless. The source stones are usually brown or off colour. Recommended for gemmologists / appraisers who are taking MSG "Advanced Diamond Program".