Please cite this website as:

Buzgar N., Apopei A. I., Buzatu A. (2009) - Romanian Database of Raman Spectroscopy (http://rdrs.uaic.ro)



EMAIL subscription



SPAFMSR

PNII - IDEI COD 2119/2008




Alexandru Ioan Cuza UniversityFaculty of Geography and Geology

Locations of visitors to this page

Why donate? If you use this site regularly and would like to help us, please consider donating a small sum.
All proceeds go to:
+ development of this website;
+ buy some minerals not available yet;
+ development of RDSS software;
+ buy some articles or books necessary for Raman study (interpretation).

Don't forget to bookmark us! | Share this page



06 Hoiseşti L11

Sample image with white, black and red pigment
large image

You can move the loupe anywhere you want. Also, you can hide the magnifier loupe by clicking the 'switch' button (placed in the bottom of the image).

You have the possibility to zoom in the spectrum by selecting a spectral region you need to be increased (along axis x); to zoom keep the left mouse-click continously pressed, drag (to left or to right) and release the left button. To return to the initial size spectrum, press the right click on the spectrum -> Zoom -> Reset View.

Raman spectrum of white pigment - Raman spectrum of Quartz
Toggle Grid Toggle Coordinates Reverse Spectrum Download Raman spectrum of white pigment .spc or .txt
Legend: white pigment______ and quartz______ Download Raman spectrum of quartz standard .spc or .txt
Raman spectrum of black pigment - Raman spectrum of Jacobsite
Toggle Grid Toggle Coordinates Reverse Spectrum Download Raman spectrum of black pigment .spc or .txt
Legend: black pigment______ and jacobsite______ Download Raman spectrum of jacobsite standard .txt
Raman spectrum of red pigment - Raman spectrum of Quartz
Toggle Grid Toggle Coordinates Reverse Spectrum Download Raman spectrum of red pigment .spc or .txt
Legend: red pigment______ and quartz______ Download Raman spectrum of quartz standard .spc or .txt
Interpretation of the white, black and red pigment Raman spectra

The Raman spectra of the white pigment are defined by background noise (BN) and strong fluorescence (F). The lack of any Raman bands, even weak ones, is due to a kaolinite clay. Constantinescu et al. (2007) have shown through XRD studies that the white pigment is a light clay (type kaolin), but the same authors mention Ca as the major chemical element in the white pigment (kaolinite clay has a low concentration of Ca, the main elements being Si and Al). Calcium carbonate is certainly absent from the white pigment, because it has a good Raman signal, at least at 1087 cm-1 (Buzgar and Apopei, 2009).

The red pigment studied contains hematite and, more frequently, quartz. The Raman spectra recorded on fine sherds from Hoiseşti and Scânteia are very similar and present the main bands of hematite. The diffuse shape of the Raman bands is caused by the fine granulation of hematite. Also, this is confirmed by high intensity peaks in the 200-300 cm-1 region and a low intensity at 1320 cm-1, which is the most intense Raman band of hematite in large crystals (Zoppi et al., 2008; Buzgar et al., 2009).

The presence of quartz is proved by the most intense band at ~465 cm-1

Quartz gives a Raman signal which is more intense than that of hematite, therefore hematite bands are less obvious in the Raman spectra.

The presence of both hematite and quartz in the red pigment excludes the use of Fe oxyhydroxides as pure red pigment. For the red color, red clay, washed several times, a process that enriched the clay with Fe oxyhydroxides (+quartz), was used. This known process is used even nowadays by pottery artisans. The source of this clay is not a special issue, as it is commonly found interbeded throughout sedimentary deposits of the Moldavian Platform.

The black pigment studied contains jacobsite. This mineral was also reported by Constantinescu et al. (2007). It is possible that it originates from the weathering crust of the Mn accumulations from Suceava county, as shown by Constantinescu et al. (2007), but we believe otherwise for two reasons. Firstly, in all samples, spectra indicated the presence of jacobsite as the only Mn mineral (absence of Mn carbonates or silicates). Secondly, several samples of black Mn corpuscles were provided by archaeologists from the “Ştefan cel Mare” University of Suceava. These Mn corpuscles were used as pigments in the Cucutenian age. Preliminary data (morphology, mineralogical composition) indicated the Nikopol manganese ore basin from Ukraine as source of these corpuscles.

References

• Jacobsite spectrum from the RRUFF project [link]

• BUZGAR N., BODI G., AŞTEFANEI D., BUZATU A. (2010) - The Raman study of white, red and black pigments used in Cucuteni Neolithic painted ceramics. Analele Stiintifice ale Universitatii “Al. I. Cuza” - Iasi, Tome 56, issue 1 [link]

• BUZGAR N., APOPEI A. I. (2009) - The Raman study on certain carbonates. Analele Stiintifice ale Universitatii “Al. I. Cuza” - Iasi, Tome 55, issue 2, 97-112 [link]

• Constantinescu, B., Bugoi, R., Pantos, E., Popovici, D., 2007. Phase and chemical composition analysis of pigments used in Cucuteni Neolithic painted ceramics. Documenta Prehistorica, XXXIV, 281-288.

• Zoppi, A., Lofrumento, C., Castellucci, E.M., Sciau, Ph., 2008. Al-for-Fe substitution in hematite: the effect of low Al concentrations in the Raman spectrum of Fe2O3. Journal of Raman Spectroscopy, 39, 40-46.