Analysis of Topaz Gemstones with Modern Spectroscopic Techniques
Sprache des Vortragstitels:
16 th Austrian Chemistry Days
Sprache des Tagungstitel:
Topaz is a rather common gemstone frequently used in jewelry because of its hardness
and good optical properties. It can be found in many places in gem quality and holds the
record for the largest gemstones on earth, e.g. the 31.000 ct El Dorado topaz. When it
comes in white to yellow colors it is a rather cheap material, but special colors such as
orange, pink and red are very rare and therefore highly thought after - good stones
often reach several hundred ? per ct and more.
However, it is often not only the color but a specific location which increases the prices
of gemstones and we have therefore investigated samples from the most important topaz
mines to see if it is possible to differentiate between them using nondestructive methods
such as Infrared or Raman microscopy. Laser Ablation icp MS was also used, which
can be called minimal invasive as it produces craters in the size of 10 µm that are not
visible to the unaided eye. In order to broaden the data set some specimens have also
been analyzed by destructive testing, using e.g. icp MS, ATR FTIR and by analysis of
common impurities .
In this paper we would like to present the combined data obtained from orange imperial
topaz (Ouro Preto, Brazil) in comparison to orange topaz from Volodarsk Volyn,
Ukraine, which can be clearly differentiated with our methods.