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Buzgar N., Apopei A. I., Buzatu A. (2009) - Romanian Database of Raman Spectroscopy (



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PNII - IDEI COD 2119/2008

Alexandru Ioan Cuza UniversityFaculty of Geography and Geology

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27 Hoiseşti L11

Sample image with 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 red pigment - Raman spectrum of Anatase and Quartz
Toggle Grid Toggle Coordinates Reverse Spectrum Download Raman spectrum of red pigment .spc or .txt
Legend: red pigment___, anatase___ and quartz___ Download Raman spectrum of anatase standard .spc or .txt
Download Raman spectrum of quartz standard .spc or .txt
Interpretation of the red pigment Raman spectra

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.

However, the large number of spectra acquisitions on the white pigment allowed the detection of some minerals in the kaolinite clay, quartz and TiO2 (rutile and, rarely, anatase). The presence of quartz is indicated by the Raman band at ~465 cm-1, which is the most intense line of quartz. The other Raman bands are hidden by the BN&F.

An issue is the high frequency of appearance of rutile in relation to anatase. We believe that almost all artefacts made of fine ceramics from Hoiseşti were fired at ~900°C, which determined the transformation of anatase into rutile. Another argument which supports this theory is that the black raw ceramics from Hoiseşti present artificial white temper, made of small quantities of white kaolinite clay, where anatase and certainly not rutile is present. Moreover, in this case, the firing process was conducted below 700-750°C (above this temperature, black carbon is destroyed).

The presence of quartz and TiO2 in the kaolinite clay may suggest that the clay used as white pigment has a residual nature, formed by the weathering of igneous rocks. Clay deposits of this kind are very rare and generally occur near volcanic neogen sites (Parva and Cornăiţa - Bistriţa Năsăud region; Haita, Pietrosul and Stejar Valleys – Suceava county).

We believe that the anatase-rich kaolinite used as white pigment during the Roman age (Middleton et al., 2005) is of the same genetic type, many sources of kaolinite clay formed by weathering occuring on the territory of the Roman Empire.


• 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]

• Middleton, A.P. , Edwards, H.G.M., Middleton, P.S., Ambers, J., 2005. Identification of anatase in archaeological materials by Raman spectroscopy: implications and interpretation. Journal of Raman Spectroscopy, 36, 984-987.

• 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.