Amber can be broadly divided into varieties and types for the place of its origin and occurrence. Its diversity, beauty and uniqueness is determined not only the region in which it is this "amber" created, but also the conditions and the raw material from which made.
Worldwide it is known more than one hundred varieties of fossil resins. Below are the characteristics of the two most common - Baltic amber and Colombian copal.
Let's start with the most valuable in jewelry and amber craft - Baltic amber. As we already know, Baltic amber is a fossil resin of coniferous trees, created at least 40 million years ago, about the content of succinic acid of 3 to 8%. Amber is a "living stone forever", which manifests his life changes color. This happens after exposure to air, light, and by changes in humidity and temperature. Changes in the color and structure of amber are noticeable after 15-20 years. Bright colors go into more orange, red, covered with bark.
Colombian copal is a young, numbering less than a million years old fossil resin of deciduous trees, with a content of from 0 to 3% of succinic acid. It is a resin with a greenish-yellow color. Colombian copal has a much lower degree of hardness than Baltic amber. To be suitable for the processing of jewelry, it must be repeatedly cured in an autoclave. It occurs quite often as an imitation of Baltic amber, then has "amber color" - milk, cognacs, lemon, cherry; scales are also possible.
It is therefore necessary to ask ourselves - how to check what we are actually dealing with? There are various household remedies such. Rub cotton wool soaked in acetone, heated needle, etc ... Unfortunately, these methods will not work in the case of copal cured in an autoclave. So what to do? The surest result of this study spectrometer. Upon receipt of the spectral curve in the IR - get confidence.
Below is a brief description of spectral curves in IR - for Baltic amber (photo 1) and Colombian copal (photo 2).
The most common diagnostic feature IR spectrum of Baltic amber (succinite) is called. '' Baltic shoulder '- the flat area of the spectrum in the region of 1250 - 1175 cm-1. Baltic arm is restricted to the right of the sharp maximum at 1150 ± 15 cm-1. Other features in the spectrum is succinite m.in wavenumbers a band at approx. 995 ± 15 cm -1, 888 ± 1 cm-1, 1645 cm-1 and 3080 cm-1. The older amber (degree of weathering), the flatter the Baltic arm, and the other spectral bands also are smoothed. The same type of resin that is succinct occurs in the area of Ukraine, Germany and Sambia. Thus, the appearance is very similar spectra made regardless of the place of production of amber - remains a characteristic pattern for Baltic amber.
Photo.1. Curve Spectral Infrared IR Baltic amber.
The spectrum of Colombian copal has larger number of spectral bands and narrower and more clearly separable peaks compared to the spectrum of Baltic amber. First of all, in the spectrum of copal we not recognize "the arm of the Baltic", that segment of the diagnostic Baltic amber. Bandwidth clearly the bands are occurring at wavenumbers approx. ± 888 cm-1 and 1645cm-1 and 3080 cm-1. With a high degree of transformation samples mentioned bands may be significantly weakened. In terms of characteristic Baltic amber no flat spectrum, the area 1150 - 1260 cm-1 ± features two separated intensity peaks in the range of ± 1218 cm-1.
Fot.2. Curve Spectral Infrared IR Colombian copal.
From the spectral analysis of materials provided also shows that on the basis of their FTIR-ATR, no major difficulties in distinguishing Baltic amber from digging, and more imitation amber resin contemporaries.