HIGH PRESSURE/HIGH TEMPERATURE PRODUCTION OF COLORED DIAMONDS

摘要

The present invention is directed to a method for treating discolored natura l diamonds, especially Type IaB diamond and Type IaA/B diamonds with platelets for improving their color. The method includes placing a discolored natural diamond in a pressure transmitting medium (40) which is consolidated into a pill. Next, the pill is placed into a high pressure/high temperature (HP/HT) press (10) at elevated pressure and elevated temperature within the graphite stable or diamond stable range of the carbon phase diagram for a time sufficient to improve the color of said diamond. Finally, the diamond is recovered from said press (10). Attractive yellowish-green, greenish-yellow and neon yellow-green diamonds can be made by this method.