Tips 03 Sep 2017

Infrared spectrometry

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Effective and non-invasive identification of Baltic amber is possible.

IR spectrometry is the most common method of spectroscopic analysis of Baltic amber (succinite) and other resins and plastics, often basis for its identification.

The use of this method in the study of fossil resins began in the years 1963-1964 in three research centers in Germany, the USA and Russia. In Poland, the beginning of the research of resins in the infrared can be considered T.Ratajczak's work in 1968, who used this method to study the Cretaceous resins from the region of Moravia.

In Poland, the infrared spectra (that is, the test results) are obtained by two methods - the transmission and reflection. The Amber Laboratory operating at the Amber Museum, uses a reflectance spectrometer with ATR. That method is now becoming popular in Poland. It is a fast, efficient, and most importantly, non-invasive method to identify Baltic amber as a raw material and the products made from it.

To examine amber, with spectrometer using reflection with ATR attachment, is to place the amber or amber product on a plate of diamond crystal. Then, we use a special clamp that's fixed to the test sample in such a way that the radiation beam hit the sample and the recorded signal. We study the obtained spectrum. It shows a series of intensive spectral bands that are used to identify synthetic and natural resins. For the test result to be correct sample must have a smooth, reflective surface or fracture.

With numerous spectral analysis' conducted in our laboratory, we can certainly say that there are no major difficulties in distinguishing Baltic amber from copals or imitation amber resin contemporaries. Comparing the spectrum of Baltic amber with the spectrum of Colombian copal, at first glance, you can see the difference between the two spectra. The most typical feature of Baltic amber spectrum is called "Arm of the Baltic." The spectrum of copal has a larger number of spectral bands and narrower and more clearly separated peaks in comparison to the Baltic amber. First of all, in the spectrum of copal we not recognize "the arm of the Baltic."

An obstacle to the identification of amber can be that the surface of amber is covered with a thin layer of another substance, e.g. polish. The investigator should be aware that reflected light penetrates only a thin surface without going deep into the sample.

Laboratory operating at the Amber Museum offers a certificate of authenticity of amber and its products with the release of the certificate. The cost of the issuance of the certificate for amber purchased elsewhere is 50 PLN.

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