The Czochralski method, developed by Polish scientist Jan Czochralski, was a byproduct of his investigation into the crystallization rates of metal. He accidentally dipped his pen into molten tin, instead of his inkwell, and pulled a single crystal from the melt.
When used to create synthetic gemstones, the Czochralski pulled-growth method creates ruby, sapphire, spinel, YAG (Yttrium-Aluminum-Garnet), GGG (Gadolinium-Gallium-Garnet), and alexandrite. The process involves melting the necessary ingredients in a crucible and keeping it in this liquid state throughout the process. A counter-clockwise rotating rod with a seed crystal attached is dipped into the melt and pulled very slowly away as the crucible rotates clockwise. A crystal solidifies from the melt as it is attached on one end to the seed and remains in contact with the melt on the other. This method can produce large, extremely pure crystals at a rate of 4 inches per hour. Single crystal semiconductors are also produced by this process.