HIGH PRESSURE AND HIGH TEMPERATURE PRODUCTION OF DIAMONDS

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 brea...

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Bibliographische Detailangaben
Hauptverfasser: ANTHONY, THOMAS R, KADIOGLU, YAVUZ, SMITH, ALAN C, WEBB, STEVEN W, VAGARALI, SURESH S, CASEY, JOHN K, BANHOLZER, WILLIAM F, JACKSON, WILLIAM E
Format: Patent
Sprache:eng ; fre ; ger
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Zusammenfassung: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.