1. High-Pressure High-Temperature (HPHT) Synthesis: Temperature and pressure remain the two critical factors in crystal production. In this method, diamonds are created within a ceramic vessel rather than underground; hydraulic pressure generates the necessary high pressure, while electricity produces the high heat required for carbon to crystallize around a natural diamond seed crystal measuring approximately 1 millimeter in diameter.
2. Chemical Vapor Deposition (CVD) Synthesis: Natural gas and nitrogen are heated to form a carbon plasma within a pressure chamber roughly the size of a dishwasher. This plasma continuously deposits onto a carbon substrate at the bottom of the chamber, gradually accumulating and hardening to form a diamond sheet, which is subsequently cut into gemstone shapes.
