Synthetic Ruby, Czochralski Boule.
Czochralski is both a man, Polish scientist Jan Czochralski, and a process for growing crystals. Czochralski's discovery was a byproduct of his investigation of 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 produces by this process.
See Also: Synthetic Corundum