Czochralski growth makes a synthetic crystal from a melt. A seed crystal touches the molten material and is slowly pulled up as the crystal grows.
In more detail
The method dates from the early 1900s. It is used for synthetic alexandrite, chrysoberyl, corundum and garnet. Like flame fusion, it grows crystals from a melt.
On a grading report
Labs report the stone as laboratory-grown (synthetic).
Related terms
- Synthetic gemstone: A synthetic gemstone is made in a laboratory and has essentially the same chemistry and properties as the natural gem. A synthetic ruby is ruby, made by people.
- Flame fusion: Flame fusion grows synthetic crystals by dropping fine powder through a very hot flame. The melted drops build up a crystal on a pedestal below.
- Flux growth: Flux growth is a way to grow synthetic crystals from a chemical solvent (flux). Crystals form as the hot solution slowly cools.
- Corundum: Corundum is the mineral species made only of aluminum and oxygen. Its red variety is ruby, and all its other colors are sapphire.