Paul-Louis Cyfflé's (1724-1806) search for porcelain

Seven unglazed figurines from private collections, attributed to Cyfflé's Terre de Lorraine manufacture in Lunéville (1766-1780), were subjected to porosity and scanning electron microscopic analyses to determine bulk element compositions and the composition and nature of their constituent phases. One figurine bears the mark CYFFLÉ À. LUNÉVILLE, three the mark TERRE DE LORRAINE. The studied samples pertain to four compositional groupings: (1) Two porous (18-20 % water adsorption W.A.) bodies containing milled quartz-rich frit + anhydrite (former gypsum) + phyllosilicate + Ca-rich matrix; (2) A soft-paste (artificial) porcelain body (10 % W.A.), containing quartz + calcic plagioclase (An₈₈₋₉₅) + glassy matrix. The latter is inferred to derive from a former frit. A coronitic, amorphous (as revealed by electron backscattered diffraction analysis) reaction rim is visible around the quartzes. The K-rich and Na-poor composition of the frit is best explained as a mixture of potassium nitrate, alum, calcined gypsum, sand, and moderate amounts of salt and soda; (3) A porous (23 % W.A.), hybrid porcelain body with finely milled particles of quartz, mullite-bearing hard-paste porcelain, Na-Ca-siliceous glass and metakaolinite; (4) Three hard-paste porcelain bodies, some with relict quartz, andesine plagioclase (An₃₇₋₄₅), pseudomorphs of kaolinite and the liquidus phase mullite in a glassy matrix. Well fired figurines have no W.A. due to the pervasive former melt phase, underfired figurines 7 %. These wares can contain small amounts of lead (1.8 wt% PbO) and SO₃ (0.6 wt%), suggesting the use of lead frit and gypsum. The diversity of Cyfflé's production is now better recognized. His trial-and-error experiments made use of a remarkably wide range of paste mixtures, with porcelain bodies in the French (soft-paste) and the German (hard-paste) tradition

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

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 oxide (8) and shows acicular wollastonite and tridymite crystals embedded in a glassy matrix consisting of SiO₂ (75), K₂O (12) and CaO (9). The 50–90 µm thick, transparent lead glaze (40.9 PbO) contains 47.6 SiO₂, 6.5 K₂O and 3.5 CaO and shows a 35–75 µm thick reaction zone (50 SiO₂, 30 PbO, 14 CaO) towards the body. The maximum thickness of the different paints is 50 µm, with 15 µm as mean thickness of the individual paint stroke. Two blue colours, for the dentil comb and the flower painting, are chemically distinct (colouring CoO in the dental rim 7, in the flower’s blue 2 mass%) and contain many As- and Pb- rich globules and dendrites. Pseudohexagonal shaped platelets of Pb–Sb–Sn triple oxide crystals, embedded in a colourless glassy matrix, generate the opacity and the colour of the yellow paints. Opaque olive green colours are created by the combination of such yellow crystals with a bluish, Cu and Co bearing glassy matrix. The opaque red overglaze enamel is a mechanical mix of yellow Pb–Sb oxide crystals with an iron- rich (16 Fe₂O₃) Pb–silica glass. Purple is very homogeneous and shows tiny drops of pure gold (max. diam. 0.5 µm) in a glassy matrix (47 PbO, 46 SiO₂, 5 K₂O). Violet is a mechanical blend of flower’s blue and purple. The pure (99.5 Au, 0.5 Fe₂O₃) gilt consists of several folded gold particles. The results of this study are only broadly consistent with the archival documented 18th century technologies. The compositional dissimilarities of the studied enamels suggest that each colour was independently fritted. Consequently, the original colour recipes written down by Hellot in 1753 must have been modified in the 30 years since then

Archaeometric analyses of european 18th–20th century white earthenware—a review

This study provides an overview of the few archaeometric analyses of European white earthenwares from England, France, Italy, Slovenia, and Switzerland. White earthenwares were an extremely successful mass-product between ca. 1750 and 1900. They became “the porcelain of the poor man” and replaced the older traditional pottery such as faïence. The invention of this new ceramic type took place simultaneously in England and France shortly before 1750. Contemporary recipes can be compared to the analytical results of these products. The ceramic bodies are, according to the chemical (X-ray fluorescence (XRF), scanning electron microscope- energy-dispersive X-ray spectroscopy (SEM-EDS), particle-induced X-ray emission- proton-induced X-ray emission (PIXE-PIGE) and microscopic analyses (scanning electron microscope-back scatter detector (SEM-BSE), artificial mixtures of clay + quartz + flux. Various techniques can be recognized. In England, a blend of a CaO- poor clay (with illite flux) + calcined flint is typical of the so-called creamware, whereas supplementary fluxes (Cornish stone) resulted in the Queen’s ware. In France and Central Europe, CaO-poor clays were mixed with grog (Paris) or with calcined flint/quartz pebbles/sand or with carbonates + Alk-/Pb-frits (Lorraine). Swiss CaO-rich bodies may contain bone ash or dolomite as flux. The products of the individual factories can be differentiated on the basis of their chemical composition. Micromorphological and chemical analyses revealed intensive physico-chemical reactions between the glaze and the body

Composition and technology of 18th century high magnesia faïences from Fulda

In 1996, archaeological excavations close to the ancient Fulda faïence manufacture site unearthed a rich deposit of faïence wastes (biscuits, faïences, technical ceramics). The manufacture was founded in 1741 by Prince Abbot Amand von Buseck and closed down in 1761. This first archaeometric study of a German faïence manufacture included 31 samples produced between 1742 and 1760. Analytical techniques were optical microscopy, X-ray fluorescence, X-ray diffraction and scanning electron microscopy, coupled to an energy-dispersive X-ray spectrometer. Biscuits and faïences are MgO- (5–13 wt.%) and CaO-rich (9–20 wt.%), easily distinguishable from the two French Mg-rich productions of Granges-le-Bourg and Lunéville that we know today. Three samples show high P₂O₅ (2.6–3.3 wt.%). Such unusual concentrations are not due to the admixing of crushed bones to the clay during processing, or to one of the well-known post-firing secondary contamination processes, but are caused by the presence of sharp edged, rhomboedric grains with sizes around 20–30 μm and an overall chemical composition of apatite. These fragments are interpreted to be remnants of primary phosphoritic elements, present ab initium in the clay, and give some hints as to the origin of the raw materials used. Phosphoritic layers can be found in the German Trias, mostly in dolomitic marls of the Middle Keuper. Such marls form the basement on which Fulda is built and could easily have been extracted by the Fulda manufacture. The high MgO values of the faïences can therefore be linked to the presence of dolomitic grains in the plastic raw material, corroborated by the positive MgO/CaO correlation. Firing temperatures of the faïences were, according to their XRD patterns, mostly between 950 and 1050 °C

Archaeometrical study (petrography, mineralogy and chemistry) of Neolithic ceramics from Arbon Bleiche 3 (Canton of Thurgau, Switzerland)

Le but de ce travail de doctorat a été d’étudier en détail les objets archéologiques mis à jour sur le site lacustre de Arbon Bleiche 3, village néolithique situé sur la rive Sud du lac de Constance (Suisse). Entre 1993 et 1995, le service archéologique du canton de Thurgovie a fouillé un périmètre de 1100 m2 (Leuzinger, 2000). La particularité de ce village est d’avoir été occupé pendant une très courte période (15 ans, entre 3384 et 3370 av. J.-C.), durant la période chronologique qui sépare la culture de Pfyn (3900- 3600 av. J.-C.) de celle de Horgen (3200-2800 av. J.- C.), période assez mal documentée en Suisse. La Dr. A. De Capitani a étudié le matériel céramique du site. Elle y observe des caractères des traditions Pfyn et Horgen. Les céramiques sont classées d’après leur affinités typologiques: les pots à caractéristiques Pfyn / Horgen sont séparés des formes spéciales, divisées en quatre sous-groupes: formes spéciales Pfyn (caractéristiques de la culture de Pfyn), formes spéciales Bayern (en relation avec les cultures de Altheim et Cham de Bavière), formes spéciales Boleráz (liées à l’étage Boleráz de la culture de Baden dans la partie ouest du Bassin des Carpates) et les formes spéciales indéterminées. De Capitani (2002) propose une origine locale pour les pots Pfyn / Horgen et pour les formes spéciales Pfyn. Un import de céramiques depuis l’Allemagne ou le Bassin des Carpates étant probable, le but de ce doctorat est d’affirmer ou d’infirmer cette hypothèse. Les analyses pétrographiques ont tout d’abord permis de séparer le matériel non céramique (torchis et poids de tisserand) des céramiques et des fusaïoles. Le premier groupe est fait d’une argile riche en inclusions et carbonatée ; le torchis n’étant pas dégraissé, contrairement au poids de tisserand (dégraissé par de la matière organique). Les céramiques, en revanche, sont formées d’une argile siliceuse contenant peu d’inclusions et sont dégraissées. Les céramiques ont ensuite été séparées en 10 groupes pétrographiques différents, en fonction de leur argile et de leur plus important dégraissant (granite, gabbro, rhyolite, chert, chamotte ou os). Ces groupes n’ont pas de relation directe avec les groupes typologiques. Les analyses chimiques, quant à elles, ont permis de séparer trois groupes principaux : le matériel non céramique (riche en CaO), les céramiques dégraissées à l’os (riches en P2O5) de la grande majorité des céramiques d’Arbon Bleiche 3. Du point de vue archéologique, les pots Pfyn / Horgen sont locaux. La majorité des céramiques ne pouvant pas être séparées chimiquement, nous pensons qu’elles ont aussi été produites localement. Seuls 13 échantillons sont des exceptions ; ils ne sont donc pas locaux. Malheureusement, leur chimisme ne correspond pas à celui des céramiques du bassin ouest des Carpates, lieu de production supposé (exception peut-être de un échantillon). Leur provenance n’a donc pas pu être élucidée. Seules les caractéristiques typologiques des céramiques de Arbon Bleiche 3 ont un lien avec la Bavière ou le bassin des Carpates.This PhD thesis focuses on the findings from Arbon-Bleiche 3, a Neolithic lacustrine village on the Southern shore of Lake Constance (Bodensee, Switzerland). From 1993 to 1995, 1100 m2 were excavated by the archaeological service of Thurgau (Leuzinger, 2000). The settlement was occupied during a very short period, fifteen years (3384-3370 BC) in the transitional period between Pfyn (3900- 3600 BC) and Horgen (3200-2800 BC) cultures. Dr. A. De Capitani studied the ceramics from Arbon-Bleiche 3. She observed in the ceramics several characteristics of Pfyn culture and of Horgen tradition. She made a typological classification of the ceramics separating Pfyn / Horgen pots from diverse kinds of special forms divided into four sub-groups: special forms Pfyn, special forms Bayern, special forms Boleráz and undetermined special forms. Special forms Pfyn have characteristics from the Pfyn culture, special forms Bayern have specificities in relation with Altheim and Cham cultures in Bavaria, and special forms Boleráz were related to the Boleráz stage of the Baden culture (western Carpathian Basin). For DE CAPITANI (2002), Pfyn / Horgen pots and special forms Pfyn were probably local. A research to detect a possible travel of the other special forms across Europe had to be made. This is the principal goal of this study. First, petrographical analyses permitted to separate non-ceramic material (cob fragments and loom weight) from the ceramics and spindle whorls. The first group was made of an inclusion-rich and carbonate-rich clay, without temper for the cobs and with organic temper for the loom weight. Inversely, the ceramics were manufactured with an inclusion-poor and silicate-rich clay and tempered in various ways. The ceramics were then separated into ten petrographical group according to the clay used and the main temper added (i.e. granite, gabbro, chert, rhyolite, grog and bone). These groups were not in direct relation with the typological groups of DE CAPITANI (2002). Second, chemical analyses let three main groups separate: non-ceramic material (CaO-rich) vs. bone tempered ceramics (P2O5-rich) vs. the great majority of the ceramics from Arbon Bleiche 3. From an archaeological point of view, the Pfyn / Horgen pots are thought to be local. Moreover, because the ceramics cannot be chemically split into groups, the same provenance for the other ceramics is also proposed. Only 13 samples are outliers and were surely foreign. However, a study of 14 ceramics from the western Carpathian Basin (probable import area defined by the archaeologists) did not match the chemistry of the outliers (except maybe one). Their provenance was, hence, not elucidated. Only their typological features are bound to Bavaria or to the western Carpathian Basin

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

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 overglaze enamel. Pb-Sb-reach pyrochlore (Naples Yellow) pigment was found in yellow and green overglaze enamels. The orange hue is obtained by superposing a hematite bearing red paint stroke over the yellow. These results are compared to those previously obtained by detailed OM, SEM, XRD and XRF analyses. Some of the phases identified by XRD (quartz, tridymite) are hardly detected by Raman and vice versa cristobalite was not found by XRD, most probably due to its low amount

Characterization of Maltese pottery of the Late Neolithic, Bronze Age and Punic Period by neutron activation analysis

A set of 41 samples from Tas-Silg, Malta, has been analysed by neutron activation. It contained nine ware groups formed by visual examination covering the Late Neolithic, Bronze Age and Punic Periods (c. 3000–218 BC). Despite this diversity and long time range, seven of these ware groups, including the ‘Thermi Ware’, all have a similar chemical composition and, therefore, have been made from the same clay. This points most probably to a local origin. One group from the Punic Period, containing only Bricky Red cooking ware, is chemically separate and represents a second distinct pattern probably assignable to a local production. Five amphora sherds also from the Punic Period, and consisting of a micaceous fabric, all have different chemical characteristics and are probably imports from overseas production sites of unknown location.peer-reviewe

The emergence of pottery in Africa during the tenth millennium cal BC: new evidence from Ounjougou (Mali)

New excavations in ravines at Ounjougou in Mali have brought to light a lithic and ceramic assemblage that dates from before 9400 cal BC. The authors show that this first use of pottery coincides with a warm wet period in the Sahara. As in East Asia, where very early ceramics are also known, the pottery and small bifacial arrowheads were the components of a new subsistence strategy exploiting an ecology associated with abundant wild grasses. In Africa, however, the seeds were probably boiled (then as now) rather than made into bread

Pottery kiln and drying oven from Aventicum (2nd century AD, Ct. Vaud, Switzerland): Raw materials and temperature distribution

Fireboxes of two pottery structures, excavated in 2002 at Aventicum (at present Avenches), the capital of Roman Switzerland, were studied to understand their function in the artisan quarter. Twenty-one oriented samples underwent petrographical, mineralogical and chemical analyses to determine the nature of the raw materials and the temperature distribution.Both structures are typologically different and show differing degrees of thermal impacts. Inferred maximum temperatures for kiln Structure 6, as deduced from phase associations, were as high as 1050–1200 °C. Such high temperatures are typically recorded in fireboxes of ceramic kilns. Structure 180 is proposed to have been a drying oven, as evidenced by: (1) its phase associations, pointing to maximum firing temperatures of c. 950–1050 °C, and (2) its unusual shape. Six out of seven clays from the artisan quarter revealed Ca-rich composition, but the Ca-poor one was preferentially used by Roman potters for bricks and clay binders to build the two structures. Such “refractory” clays are obviously better suited to withstand higher firing temperatures and for a longer period than Ca-rich clays