Identification of Turquoise and its Imitations with Infrared spectroscopy
Sprache des Vortragstitels:
16 th Austrian Chemistry Days
Sprache des Tagungstitel:
Turquoise is a complex basic copper aluminum phosphate best represented by the
formula Cu(Al,Fe)6(PO4)4(OH)8.4H2O. The color turquoise has been named after the
mineral and is typical for the species, although variations between green and blue can
The material has been used in jewelry since ancient times, especially in Persia and by
Indian tribes in America. Nowadays it is still popular and besides the purely natural
material several imitations or modifications are on the market. Starting from inorganic
materials which are simply soaked with color or coated with a varnish, via natural
material which has been reinforced or sintered with glass, to fully synthetic products ?
almost everything is available and has been used. Whereas conventional gemological
identification methods are rather limited with non-transparent materials, infrared
spectroscopy has proven to be a fast and powerful technique for the identification of
turquoise and its imitations (Fig. 1).