The Czochralski process is a method for the production of single crystals, solid chunks of material with a uniform crystal matrix. Such crystals are famously used in the construction of electronic components as well as in scientific research and a number of other applications where a high quality crystal with a uniform matrix is needed. Jewelers, for instance, can utilize the Czochralski process in the formation of high performance gemstones for their projects, just as research facilities with a need for materials like diamond can grow them in the lab using this technique.
This process is named for a Polish researcher who discovered it at the start of the 20th century. It starts with melting the components of the crystals in a crucible capable of tolerating extremely high temperatures. The crucible is typically positioned in a closed kiln with very precise temperature control. High control is critical, as the process will fail if the mixture is too hot or too cold, and very exact sensors may be positioned in several locations to monitor temperature changes.
When the mixture is heated with any dopant and other additions that may be necessary, a technician can carefully lower a rod with a seed crystal. This is usually done with the use of mechanical equipment, rather than by hand. Next, the rod is carefully and very slowly withdrawn as the mixture forms a solid matrix around the seed crystal. The end result of the Czochralski process should be a solid log of material, with some remainders at the bottom of the crucible.
In settings where the temperature rises too high, the seed crystal can melt. Introducing the crystal at low temperatures can cause the premature crystallization of the entire contents of the crucible, complete with cracks, fracture lines, and other impurities. This process is slow; withdrawal of the seed crystal is measured in millimeters per hour. The careful control needed throughout the Czochralski process can yield very high quality crystals with a minimum of impurities.
Production costs can depend on the raw materials needed and the size of the crystal. Larger crystals are more challenging to grow, and require greater degrees of control. Some raw components are very expensive. Czochralski process crystals are chemically identical to natural formations, but have a much higher quality and reliability. This is usually desirable in settings like labs and electronics manufacturers, but jewelers sometimes have difficulty selling lab-grown stones due to consumer preference for natural stones.