Variety and Identification of Garnet

In this paper，the common characteristics and infrared spectra of different varieties of garnets are compared in order to find a fast way to distinguish garnet.The results show it is relatively straightforward to separate pyralspite series from ugrandite series.The colour of pyralspite series usually shows warm－toned，such as red and orange，on the other hand urgrandite series often shows cool－toned such as green colour.The B－zone frequency of pyralspite infrared spectrum is higher than 870cm^－1 and there is usually no D－zone frequency.The B－zone frequency of ugrandite is lower than 870cm^－1 and it shows D－zone frequency in the infrared spectrum.Because grossular and andradite are incomplete isomorphism series，it is also relatively straightforward to separate grossular from andradite.The refractive index of grossular is lower than 1.78and the B－zone infrared frequency of grossular is at 864cm^－1.While the refractive index of andradite is higher than 1.78and the B－zone infrared frequency of andradite is at 837cm^－1.Because the pyrope，almandine and spessartine are isomorphism series，it is difficult to separate them.The colour，refractive index and infrared spectrum should be considered overall to make a accurate conclusion.