Yttrium aluminium garnet (Ce:YAG) is used as a phosphor in cathode ray tubes and white light-emitting diodes, and as a scintillator. YAG for a period was used in jewelry as a diamond and other gemstone simulant. Colored variants and their doping elements include: green (chromium), blue (cobalt), red (manganese), yellow (titanium), purple (neodymium), pink, and orange. As faceted gems they are valued (as synthetics) for their clarity, durability, high refractive index and dispersion. The critical angle of YAG is 33 degrees. YAG cuts like natural garnet, with polishing being performed with alumina or diamond (50,000 or 100,000 grit) on common polishing laps. YAG
Garnet gem garnets and was used as lapping and polishing media for the glass industries. The host rock of the garnet here is garnetiferous mica schist and the total percentage of garnet is not more than 7% to 10%, which makes the material extremely costly and non-economical to extract for non-gemstone applications. Garnet is the birthstone of January. It is also the birthstone of Aquarius in tropical astrology. New York has garnet as its state gemstone, Connecticut has almandine garnet as its state gemstone, Idaho has star garnet as its state gemstone, and Vermont has grossular garnet as its state gemstone.