Gadolinium gallium garnet
Gadolinium Gallium Garnet (GGG, Gd3Ga5O12) is a synthetic crystalline material of the garnet group, with good mechanical, thermal, and optical properties. It is typically colorless. It has cubic lattice, density 7.08 g/cm³ and Mohs hardness is variously noted as 6.5 and 7.5. Its crystals are made by Czochralski method and can be made with addition of various dopants for modification of color. It is used in fabrication of various optical components and as substrate material for magneto–optical films (magnetic bubble memory). It also finds use in jewelry as a diamond simulant. GGG can also be used as a seed substrate for the growth of other garnets such as YIG.