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
GemStone IV named "Avalon" is available for Mac OS X. No official Linux client exists. "GemStone" was first demonstrated to GEnie in 1987 before Simutronics was officially incorporated. It was only used as a demonstration model and was never available to the general subscribers. "GemStone ][" was released in April 1988 to GEnie customers. However, "GemStone ][" was very short-lived, and "GemStone III" went into open beta testing in December 1989, officially launching on February 1, 1990. The transition from "][" to "III" maintained significant portions of the environment, but not all, and character records were not maintained over the transition, requiring