Gemmological Characteristics and Mineral Components of“Fenghuang Stone”

A new kind of gem product has appeared in the jewelry market recently,which is called "Fenghuang Stone".In order to study the mineralogical and gemmological characteristics of the stones,the authors collected some samples from the market and did a series of tests and analyses.The samples were tested by using conventional gemmological methods,polarizing microscope,XRD and EPMA.Firstly, physical properties of the samples have been observed. The samples are blue and green. The green-blue, green and blue mineral exists between mineral grains or fissures in the form of infection and alternates with distribution between both of them. The samples are vitreous luster from being slightly transparent to opaque. The refractive index is between 1.51 and 1.52 by point measurement and its average is 1.519. The density is between 2. 59. and 2. 64 g/cm³ and its average is 2. 62 g/cm°. The surface of samples can not be carved by knife and ultraviolet fluorescence is inert.