It was recently announced that three inventors at the Carnegie Institution in Washington, D.C., obtained a patent related to the manufacture of a single-crystal diamond. U.S. Patent No. 7,115, 241, entitled “Ultrahard diamonds and method of making thereof,” includes seven method claims relating to diamond manufacture. The first claim of the patent is a method for manufacture a hard single crystal diamond comprising “growing a single crystal diamond; and annealing the single crystal diamond at pressures in excess of 4.0 GPa and a temperature in excess of 1500 degrees C to have a hardness in excess of 120 GPa.” According to the patent, “natural diamonds have a hardness between 80 [and] 120 GPa,” and “[m]ost grown or manufactured diamonds, regardless of the process, have a hardness of less than 110 GPa.” According to the ag-IP-news article (link below), the inventors are members of a high-pressure research team and “[t]hey and their colleagues subject matter to intense pressures and temperatures and have discovered previously unknown fundamental properties and structures of matter, while creating entirely new substances along the way.” The three inventors on this patent are Russell Hemley, Ho-kwang Mao, and Chih-Shiue Yan.

U.S. Patent No. 7,115,241: LINK
ag-IP-news Article: LINK
Carnegie Institution Press Release: LINK
Carnegie Institution Website: LINK