Université de Fribourg

Unexpected presence of 14C in inorganic pigment for an absolute dating of paintings

Beck, Lucile ; Messager, Cyrielle ; Caffy, Ingrid ; Delqué-Količ, Emmanuelle ; Perron, Marion ; Dumoulin, Jean-Pascal ; Moreau, Christophe ; Degrigny, Christian ; Serneels, Vincent

In: Scientific Reports, 2020, vol. 10, no. 1, p. 9582

The absolute dating of paintings is crucial for tackling the problem of fake art. Investigations to authenticate paintings rely on an advanced knowledge of art history and a collection of scientific techniques. Radiocarbon dating is the only technique that gives access to an absolute time scale, but its application is limited to organic materials such as wood, canvas or natural binder....

Université de Fribourg

Non-invasive Raman identification of crystalline and glassy phases in a 1781 Sèvres Royal Factory soft paste porcelain plate

Colomban, Philippe ; Maggetti, Marino ; Albis, Antoine d’

In: Journal of the European Ceramic Society, 2018, vol. 38, no. 15, p. 5228–5233

A Raman study of a Sèvres soft paste (frit) porcelain plate allowed the identification of both the crystalline and amorphous phases. Cristobalite and pseudowollastonite gave main Raman signatures in the body where also tridymite, amorphous alkali silicate glass and lead arsenate apatite were detected. Na0.4K0.1Ca0.5Pb4(AsO4)3 lacunar apatite is identified as opacifier in blue and green...

Université de Fribourg

A model based two-stage classifier for airborne particles analyzed with Computer Controlled Scanning Electron Microscopy

Meier, Mario Federico ; Mildenberger, Thoralf ; Locher, René ; Rausch, Juanita ; Zünd, Thomas ; Neururer, Christoph ; Ruckstuhl, Andreas ; Grobéty, Bernard

In: Journal of Aerosol Science, 2018, vol. 123, p. 1–16

Computer controlled scanning electron microscopy (CCSEM) is a widely-used method for single airborne particle analysis. It produces extensive chemical and morphological data sets, whose processing and interpretation can be very time consuming. We propose an automated two-stage particle classification procedure based on elemental compositions of individual particles. A rule-based classifier is...

Université de Fribourg

Iron isotope fractionation in subduction-related high-pressure metabasites (Ile de Groix, France)

El Korh, Afifé ; Luais, Béatrice ; Deloule, Etienne ; Cividini, Damien

In: Contributions to Mineralogy and Petrology, 2017, vol. 172, no. 6, p. 41

Characterisation of mass transfer during subduction is fundamental to understand the origin of compositional heterogeneities in the upper mantle. Fe isotopes were measured in high-pressure/low-temperature metabasites (blueschists, eclogites and retrograde greenschists) from the Ile de Groix (France), a Variscan high-pressure terrane, to determine if the subducted oceanic crust contributes to...

Université de Fribourg

Phase and compositional analysis of a Sèvres soft paste porcelain plate from 1781, with a review of early porcelain techniques

Maggetti, Marino ; D’Albis, Antoine

In: European Journal of Mineralogy, 2017, p. -

Optical microscopy, X-ray diffraction, X-ray fluorescence and scanning electron microscopy analyses were carried out on a typical Sèvres soft (frit) porcelain plate from 1781 in order to determine the chemical and mineralogical composition as well as the microstructure of its ceramic body, glaze, overglaze decoration and gilding. The body is rich in SiO₂ (73 mass%), CaO (16) and alkali...

Université de Fribourg

The origin of 18th–19th century tin-glazed pottery from Lorraine, France

Maggetti, Marino ; Rosen, J. ; Serneels, Vincent

In: Archaeometry, 2015, vol. 57, no. 3, p. 426–452

Forty-eight tin-glazed ceramic fragments (faiences) from Lorraine, found in excavations or pertaining to objects in collections, were subjected to X-ray fluorescence analysis to determine the bulk, major, minor and trace element compositions. Sixteen superficially clay layers from the surroundings of Lunéville and Saint-Clément were also analysed. The faiences are, with four exceptions, MgO...

Université de Fribourg

How mineralogy and geochemistry can improve the significance of Pb isotopes in metal provenance studies

Baron, S. ; Tămaş, Calin-Gabriel ; Carlier, C. Le

In: Archaeometry, 2014, vol. 56, no. 4, p. 665–680

Lead isotopes combined with trace element data represent a powerful tool for non-ferrous metal provenance studies. Nevertheless, unconsidered geological factors and archaeological data, as well as ignored analytical procedures, may substantially modify the interpretation of the isotopic and trace element signature obtained as a potential ore candidate. Three archaeological examples, accompanied...

Université de Fribourg

Alburnite, Ag₈GeTe₂S₄, a new mineral species from the Roşia Montana Au-Ag epithermal deposit, Apuseni Mountains, Romania

Tămaş, Călin G. ; Grobety, Bernard ; Bailly, Laurent ; Bernhardt, Heinz-Juergen ; Minuţ, Adrian

In: American Mineralogist, 2014, vol. 99, no. 1, p. 57–64

Alburnite, ideally Ag₈GeTe₂S₄, was discovered in the Cârnicel vein from the Roşia Montana epithermal Au-Ag ore deposit, Apuseni Mountains, Romania. The new mineral is associated with tetrahedrite, galena, pyrite, sphalerite, chalcopyrite, and tellurides (hessite, altaite, and sylvanite). Associated gangue minerals are rhodochrosite, quartz, calcite, and rhodonite. Alburnite was observed...