The hydrothermal process requires an intense amount of heat and pressure to form crystals from elements. A set of compatible, stable elements placed under high heat causes a reaction, forming crystals with different features. CVD Chemical vapor deposition (CVD) is an effective method used to grow hard crystals. The process supports crystalline growth in a chamber where carbon at... https://www.gemsngems.com/product-category/lab-created/hydrothermal-pulled-czochralski-gemstones/hydrothermal-emerald/