Gadolinium gallium garnet

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Gadolinium Gallium Garnet
Category synthetic mineral
(repeating unit)
Color transparent, colorless to light brown or yellow. May also be orange or blue.[1]
Crystal system cubic
Mohs scale hardness 6.5[1] (other sources 7.5)
Luster vitreous to subadamantine[1]
Specific gravity 7.05 (+.04, -.10)[1]
Density 7.08 g/cm3
Polish luster vitreous to subadamantine[1]
Optical properties Single refractive[1]
Refractive index 1.970 (+.060)[1]
Birefringence none[1]
Pleochroism none[1]
Dispersion .045[1]
Ultraviolet fluorescence moderate to strong pinkish orange in shortwave[1]

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).[2] 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.[3]

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  1. ^ a b c d e f g h i j k l (Gia), Gemological. Gem Reference Guide. City: Gemological Institute of America (GIA), 1988. ISBN 0-87311-019-6
  2. ^ J. F. Greber "Gallium and Gallium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2012 Wiley-VCH, Weinheim. doi:10.1002/14356007.a12_163
  3. ^ Holm, U., Sohlstrom, H., & Brogardh, T. (1984). YIG-Sensor Design for Fiber Optical Magnetic-Field Measurements. Proceedings of the Society of Photo-Optical Instrumentation Engineers, 514, 333–336. Retrieved from <Go to ISI>://A1984AHQ9500058

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