High pressure and high temperature production of diamonds

本发明涉及一种用于处理变色的天然钻石的方法，特别是对IIa级钻石和主要以氮作为B核心的IaA/B级钻石进行处理的方法。该方法包括：将一变色的天然钻石预先分块和预先成形，以防止它在高压/高温(HP/HT)压制过程中破裂，将该变色的天然钻石埋入被压实成丸剂的压力传递介质中。然后，将该丸剂放入高压/高温(HP/HT)压机内暴露在碳相图的石墨稳定区或钻石稳定区内的高压和高温下保持一段时间，该时间足以改进该钻石的颜色。最后从所述压机中重新获得该钻石，由该方法可获得无色的和各种颜色的钻石。 The present invention is directed to a method for treating discolored natural diamond, especially Type IIa diamond and Type IaA/B diamond with nitrogen as predominantly B centers, for improving its color. The method includes preblocking and preshaping a discolored natural diamond to prevent its breakage in a high pressure/high temperature (HP/HT) press, placing said discolored natural diamond in a pressure transmitting medium which is consolidated into a pill. Next, the pill is placed into a HP/HT press 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. Colorless and fancy colored diamonds can be made by this method.