Garnet shades of green, beige, brown, gray, and blue, but in incandescent light, they appear a reddish or purplish/pink color. This is the rarest type of garnet. Because of its color-changing quality, this kind of garnet resembles Alexandrite. Andradite is a calcium-iron garnet, CaFe(SiO), is of variable composition and may be red, yellow, brown, green or black. The recognized varieties are topazolite (yellow or green), demantoid (green) and melanite (black). Andradite is found both in deep-seated igneous rocks like syenite as well as serpentines, schists, and crystalline limestone. Demantoid has been called the "emerald of the Urals" from its occurrence there,
Gadolinium gallium garnet can also be used as a seed substrate for the growth of other garnets such as YIG. Gadolinium gallium garnet Gadolinium Gallium Garnet (GGG, ) is a synthetic crystalline material of the garnet group, with good mechanical, thermal, and optical properties. It is typically colorless. It has a cubic lattice, a density of 7.08 g/cm and its Mohs hardness is variously noted as 6.5 and 7.5. Its crystals are produced with the Czochralski method. During production, various dopants can be added for colour modification. The material is also used in fabrication of various optical components and as a substrate material