structural:reformatting, quality:correction, information:filtering, structural:expansion
Czochralski process (melt process)

In 1918 this process was developed by J. Czocharalski and is also referred to as the "crystal pulling" method. In this process, the required gemstone materials are added to a crucible. A seed stone is placed into the melt in the crucible. As the gem begins to crystallize on the seed, the seed is pulled away and the gem continues to grow. This is used for corundum but is currently the least popular method.