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Center of scientific gemmology

Mineral- and Gemstone Analysis

By using vibrational spectroscopy such as Infrared or Raman we determine the nature of minerals or facetted gemstones. One goal of this project is to generate a major database of referenced samples of known locality and treatment in order to not only be able to identify unknown samples, but also to assign the material to certain localities – in the best case to the mine where the stone was found.
Inclusions are unwanted in facetted stones, however, they can help tremendously in the identification and determination of origin. With confocal Raman microscopy we can not ónly look at these inclusions, we can even identify them on basis of their Raman spectra – without the need to destroy the sample.

 

Another way of getting valuable information is chemical analysis of a sample. With icp MS we can „atomize“ the sample and identify almost all chemical elements, typically down to the parts per million range. In order to get this information a small amount of the mineral (around 10 mg) has to be dissolved in a microwave assisted high pressure vessel or a solid sample is can be directly analyzed using laser ablation. The latter process is almost non destructive and therefore well applicable for gemstones analysis (like determination of beryllium diffusion in sapphires).

Instrumentation:
Thermo Scientific DXR Raman microscope with fiber optic, various lasers and liquid nitrogen option
Thermo Scientific iN10 MX FTIR microscope mit iZ10 accesory
Thermo Scientific Contiuµm FTIR microscope with Nicolet 5700 spectrometer
Thermo Scientific X series II icp MS
Cetac Laser ablation system LSX-213 G2+
CEM microwave dissolution system