Czochralski Process (Crystal Pulling Technique)
Also known as the crystal pulling technique has a number of technical applications, since large crystals of good purity and optical homogeneity are obtained.
How gemstones are synthesized by czochralski process?
- The source material is melted in a container (usually made of iridium) in an inert-gas atmosphere.
- A rotating rod with a seed crystal is lowered until it touches the melt.
- It is then slowly raised, allowing the molten source material, to solidify as the seed is slowly pulled from the melt.
- The product obtained is a tabular boule which is virtually flawless.
- Crystals which have lower melting points can be synthesized in the open, while high melting materials require a shield to control heat loss.
Gemstones synthesized by this method are:
- Synthetic Corundum (Synthetic Ruby and Synthetic Sapphire)
- Synthetic Alexandrite
- Yttrium Aluminium Garnet (various colours)
- Gadolinium Gallium Garnet (various colours)