The conventional methods of the gemmology and the modern instruments of electronic probe, ultraviolet-visible spectrophotometer, Fourier transform infrared spectrometer, cathodoluminescence spectrometer are used to research and analyse the flux-grown synthetic spinel and compare them with the natural spinels.

Since the introduction of melting acceleration technique by coal-oxygen injection in the electric are furnace operation the heat supply has changed from partial supply pattern into a new one on a large area and multi point basis, and as a result the syn- chronous melting of furnace charge has replaced the previous mode of gradually melting.