Diamond is the queen of jewelry. Due to the well-known slogans, such as “diamond is girl’s best friend”, diamond has become the symbol of love, particularly for wedding ceremonies. In 2007, about $14B rough diamonds were sold to the polishers that were eventually supplied to the retail gem market of about $70 billion sales worldwide. Among the polished gems, about $100 million were synthesized under ultrahigh pressure and temperature by Gemesis and others. In 1970s, General Electric (GE) pioneered the gem diamond growth by using belt apparatuses that were capable to sustain a pressure of 5.5 GPa and a temperature of 1300°C. The diamond was formed by feeding micron diamond fines to a molten catalyst of iron nickel alloy. The diamond fines were dissolved in the liquid and precipitated onto a diamond seed. GE’s gem diamond growth was costly and the process very slow. In 1980s, Sumitomo Electric used the similar technique to grow larger crystals.