settlement suggest that its inhabitants practiced both the amber trade and processing. The discovery of the commercial and craft amber center in Partynice plays
important role in history in Silesian (west-south Poland) archaeology and is still the
most convincing evidence concerning the course of the Amber Road and the role
that Wrocław area played in it.
As a method of choice, the FT-Raman spectroscopy was implemented in the
investigations. The Raman spectra of analyzed samples and reference materials
were collected using a Raman research system FT-Nicolet Magma 860 employing
for excitation In:Ga:Ar laser line at 1064 nm. The spectra were recorded at the
room temperature in the range 100–3800 cm
−1 with the spectral resolution 4 cm
−1
and with a constant number of scans (512/measurement). The laser power at the exit
has been set below 0.8 W and was chosen separately for each sample. The
archeological samples were analyzed without any sampling. Due to the huge
number of the objects varying in color, the analyses were carried out after the
selection of the reference samples.
A comparative analysis of excavated artifacts and reference materials originating
from amber sources within reasonable proximity to the excavations was performed.
Two deposits were considered: deposit of the Baltic amber (Poland and Russia) and
deposit from Moravia (Czech Republic). Reference materials including succinite
(Baltic amber) from tertiary deposit at the seashore from North Harbor in Gdansk
(Poland) and Sambian Peninsula, Yantarny near Kaliningrad (Russia), valchovite
from Valchov in Moravy (Czech Republic) dated back to Upper Cretaceous were
used.
Analysis of Raman spectra allows differentiating amber material of various
geological and geographical origins. There are three wave numbers regions
observed in amber Raman spectra that permit proper origin assignment. The first
region covers high wave number area from 3700 to 2000 cm
−1 ; the second and the
third regions cover low wave number areas from 2000 to 1100 cm
−1 and from 1100
to 100 cm
−1 , respectively. The main spectral feature that could be used as a guide
and help in distinguishing between various kinds of amber is the intensity ratio of
two bands at about 1449 and 1645 cm
−1 . The ratio can be used as an indicator of
the maturity level of the analyzed sample and its geological age [134].
Traditionally, Baltic amber has been characterized according to the band present
at 1150 cm
−1 in the Raman spectra assigned to succinic acid and its esters and the
intensity ratio of peaks at 1645 cm
−1 (m (C=C)) and 1450 cm
−1 (d (CH 2 ,CH 3 )). The
spectra of Baltic and Moravian amber reveal some differences in the normalized
intensity of the characteristic bands [127]. Samples of valchovite and succinate
amber show intensity ratios ranging between 0.48–0.63 and 0.62–0.86, respectively, allowing differentiation of these two kinds of amber. The I 1645 /I 1449 ratio is
higher for succinite (Baltic amber) what suggests much higher degree of maturity
and different geological ages [135]. High repeatability of Raman spectra collected
for analyzed amber samples discovered in the excavation was noticed. The position
of the characteristic bands and their relative Raman intensity observed in the spectra
of analyzed samples and reference material (succinite) from North Harbor in
Gdansk (Poland) and Sambian Peninsula, Yantarny near Kaliningrad (Russia)
498
T. Łojewski and B. Łydżba-Kopczyńska
important role in history in Silesian (west-south Poland) archaeology and is still the
most convincing evidence concerning the course of the Amber Road and the role
that Wrocław area played in it.
As a method of choice, the FT-Raman spectroscopy was implemented in the
investigations. The Raman spectra of analyzed samples and reference materials
were collected using a Raman research system FT-Nicolet Magma 860 employing
for excitation In:Ga:Ar laser line at 1064 nm. The spectra were recorded at the
room temperature in the range 100–3800 cm
−1 with the spectral resolution 4 cm
−1
and with a constant number of scans (512/measurement). The laser power at the exit
has been set below 0.8 W and was chosen separately for each sample. The
archeological samples were analyzed without any sampling. Due to the huge
number of the objects varying in color, the analyses were carried out after the
selection of the reference samples.
A comparative analysis of excavated artifacts and reference materials originating
from amber sources within reasonable proximity to the excavations was performed.
Two deposits were considered: deposit of the Baltic amber (Poland and Russia) and
deposit from Moravia (Czech Republic). Reference materials including succinite
(Baltic amber) from tertiary deposit at the seashore from North Harbor in Gdansk
(Poland) and Sambian Peninsula, Yantarny near Kaliningrad (Russia), valchovite
from Valchov in Moravy (Czech Republic) dated back to Upper Cretaceous were
used.
Analysis of Raman spectra allows differentiating amber material of various
geological and geographical origins. There are three wave numbers regions
observed in amber Raman spectra that permit proper origin assignment. The first
region covers high wave number area from 3700 to 2000 cm
−1 ; the second and the
third regions cover low wave number areas from 2000 to 1100 cm
−1 and from 1100
to 100 cm
−1 , respectively. The main spectral feature that could be used as a guide
and help in distinguishing between various kinds of amber is the intensity ratio of
two bands at about 1449 and 1645 cm
−1 . The ratio can be used as an indicator of
the maturity level of the analyzed sample and its geological age [134].
Traditionally, Baltic amber has been characterized according to the band present
at 1150 cm
−1 in the Raman spectra assigned to succinic acid and its esters and the
intensity ratio of peaks at 1645 cm
−1 (m (C=C)) and 1450 cm
−1 (d (CH 2 ,CH 3 )). The
spectra of Baltic and Moravian amber reveal some differences in the normalized
intensity of the characteristic bands [127]. Samples of valchovite and succinate
amber show intensity ratios ranging between 0.48–0.63 and 0.62–0.86, respectively, allowing differentiation of these two kinds of amber. The I 1645 /I 1449 ratio is
higher for succinite (Baltic amber) what suggests much higher degree of maturity
and different geological ages [135]. High repeatability of Raman spectra collected
for analyzed amber samples discovered in the excavation was noticed. The position
of the characteristic bands and their relative Raman intensity observed in the spectra
of analyzed samples and reference material (succinite) from North Harbor in
Gdansk (Poland) and Sambian Peninsula, Yantarny near Kaliningrad (Russia)
498
T. Łojewski and B. Łydżba-Kopczyńska