Quartz crystals are grown and manufactured using an autoclave. The process creates hydrothermal quartz, which are also known as cultured or synthetic quartz.
Synthetic gemstones have been grown and manufactured since the late 19th century. Such man-made crystals have had industrial purposes:
- Laser technology
Man-made crystals are also used for jewelry. Man-made stones are not as rare as natural gems, but can be made in similar size, clarity and color. Because of the possibility of fraud, the United States Federal Trade Commission requires synthetic gems and crystals to have descriptions that clearly identify them so they are not mistaken for natural ones.
Grown or manufactured quartz crystal is also known as hydrothermal, cultured or synthetic quartz. It is created inside an autoclave, a specialized piece of equipment that produces high levels of internal pressure and heat. To grow quartz, the autoclave must produce 21,000 pounds per square inch of internal pressure and temperatures above 200 degrees Celsius.
Crushed silicon dioxide, known as silica, is placed in the autoclave and serves as the source material for the quartz crystals. The process requires water and slices of quartz as well, which are placed in the autoclave as a place for the synthetic crystals to grow. As the autoclave is heated, the temperature increases, and changes begin to occur.
First, the water becomes steam and dissolves the crushed silica. Second, the steam rises and carries the dissolved silica to the top, where it attaches to the quartz and begins to grow as new crystals.