The color index analysis of turquoise

Turquoise is a kind of natural jade and stone stuff which consists of Cu,Al and H₂O bearing phosp hate(CuAl₆PO₄₄(OH)₈·4H₂O).From the Stone Age to nowdays,turquoise has aprosperou shistory for 6 000～7 000 years.To Moslem,turquoise is considered a kind of luck and talisman.Atradition about turquoise is that it was in troduced to Europe from Turkey,so turquoise has also been called "turkey jade",in addition,turquoise can also be used as adornment and carve stuff. In the world,Chinese,America, pre-Russia,Egypt and Iran,and so on,are the main turquoise productive countries. Chinese turquoise has been well-known for a long time,and the deposits are situated in East Qinling,particularly center in south west edge of Wudang mounta in up heaval. Turquoise's maintrait is its color that is from sky blue to green, striking,radiant and enchanting. Along with the development of the natural science people deepen the color know ledge gradually,for example,written language description is not contented to the needs in some field, and the need is quan titative analysis. Color index can show the cha racteristics of color exactly. For adapting the development,the authors use the metal-bearing ore's color index analysis for the first time through reflectance determining and the colorimetry theory,and analy ses 4 turquoises' color index in various color. So the color of turquoise is quantitated successfully.