A process used for growing single crystals. It involves melting a material in a crucible. A single crystal of the material is lowered onto the surface and drawn slowly upwards producing a cylindrical crystal known as a boule. The process is used to grow single crystals that have a high value, such as crystals of silicon and germanium used in the semi-conductor industry, and pure metals, such as platinum, silver, and gold, and synthetic gemstones. It is named after the Polish chemist Jan Czochalski (1885–1953) who invented the process in 1916.