Hydrothermal growth makes synthetic crystals in a hot water solution under high pressure.
In more detail
It is the only successful method for growing synthetic quartz, including synthetic amethyst. Hydrothermal synthetic emerald for jewelry appeared in 1960. These emeralds often show zigzag, chevron-like growth lines.
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.
- Flux growth: Flux growth is a way to grow synthetic crystals from a chemical solvent (flux). Crystals form as the hot solution slowly cools.
- Quartz: Quartz is the mineral species of amethyst and citrine. It is silicon dioxide in a trigonal crystal.
- Emerald: Emerald is the green to bluish green variety of the mineral beryl. Chromium, vanadium or both cause its color.
- Amethyst: Amethyst is the purple variety of quartz. Iron in the crystal, together with natural radiation, causes its color.