Synthetic Quartz
A collection of synthetic quartz crystals that were manufactured in Russia.
The hydrothermal transport method is used in a large autoclave to grow the quartz. An autoclave is an heated, pressurized container about 10 feet tall. It contains an aqueous solution of sodium carbonate or sodium hydroxide. Fragments of quartz are placed near the bottom of the autoclave. When heated, these fragments dissolve in the basic solution and become the nutrient solution for the growth of the seed crystals. In the upper portion of the container is a basket in which many small seed crystals of quartz are suspended (typically by an inert metal wire). When the temperature is raised to about 700 degrees F, the quartz fragments dissolve. Because the lower section is warmer than the top section, a convective current is created that transports the silica saturated solution up to the seed crystals. The seeds grow by the precipitation of the silica from the solution. This under saturated solution then sinks down to the heated quartz fragment area to become saturated and, again, rise back up to the growing seed crystals.
After World War II, it was obvious that a huge demand for flawless quartz crystals was required for electronic components, The autoclave method was designed in the late 1940's to produce colorless quartz for industrial applications. It was not until 1956 that Western Electric (Bell Systems) laboratories was able to mass produce acceptable quality and quantities of synthetic quartz crystals.
Soon afterwards, impurities were added to create colored quartz crystals, some of which are not naturally known.
Autoclave reference:
Synthetic Quartz
A collection of synthetic quartz crystals that were manufactured in Russia.
The hydrothermal transport method is used in a large autoclave to grow the quartz. An autoclave is an heated, pressurized container about 10 feet tall. It contains an aqueous solution of sodium carbonate or sodium hydroxide. Fragments of quartz are placed near the bottom of the autoclave. When heated, these fragments dissolve in the basic solution and become the nutrient solution for the growth of the seed crystals. In the upper portion of the container is a basket in which many small seed crystals of quartz are suspended (typically by an inert metal wire). When the temperature is raised to about 700 degrees F, the quartz fragments dissolve. Because the lower section is warmer than the top section, a convective current is created that transports the silica saturated solution up to the seed crystals. The seeds grow by the precipitation of the silica from the solution. This under saturated solution then sinks down to the heated quartz fragment area to become saturated and, again, rise back up to the growing seed crystals.
After World War II, it was obvious that a huge demand for flawless quartz crystals was required for electronic components, The autoclave method was designed in the late 1940's to produce colorless quartz for industrial applications. It was not until 1956 that Western Electric (Bell Systems) laboratories was able to mass produce acceptable quality and quantities of synthetic quartz crystals.
Soon afterwards, impurities were added to create colored quartz crystals, some of which are not naturally known.
Autoclave reference: