39 research outputs found
Paul-Louis Cyfflé's (1724-1806) search for porcelain
Seven unglazed figurines from private collections, attributed to CyfflĂ©'s Terre de Lorraine manufacture in LunĂ©ville (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 CYFFLĂ Ă. LUNĂVILLE, 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 (Anâââââ
) + 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 (Anâââââ
), 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 SOâ (0.6 wt%), suggesting the use of lead frit and gypsum. The diversity of CyfflĂ©'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 SĂšvres 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 SĂšvres 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 SiOâ (73 mass%), CaO (16) and alkali oxide (8) and shows acicular wollastonite and tridymite crystals embedded in a glassy matrix consisting of SiOâ (75), KâO (12) and CaO (9). The 50â90 ”m thick, transparent lead glaze (40.9 PbO) contains 47.6 SiOâ, 6.5 KâO and 3.5 CaO and shows a 35â75 ”m thick reaction zone (50 SiOâ, 30 PbO, 14 CaO) towards the body. The maximum thickness of the different paints is 50 ”m, with 15 ”m 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 flowerâs blue 2 mass%) and contain many As- and Pb- rich globules and dendrites. Pseudohexagonal shaped platelets of PbâSbâSn 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 PbâSb oxide crystals with an iron- rich (16 FeâOâ) Pbâsilica glass. Purple is very homogeneous and shows tiny drops of pure gold (max. diam. 0.5 ”m) in a glassy matrix (47 PbO, 46 SiOâ, 5 KâO). Violet is a mechanical blend of flowerâs blue and purple. The pure (99.5 Au, 0.5 FeâOâ) 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
Technological aspects of an erly 19th c. English and French white earthenware assemblage from Bern (Switzerland)
Archaeometric analyses of european 18thâ20th century white earthenwareâa 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 âthe porcelain of the poor manâ and replaced the older traditional pottery such as faĂŻence. 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 Queenâs 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 faĂŻences from Fulda
In 1996, archaeological excavations close to the ancient Fulda faĂŻence manufacture site unearthed a rich deposit of faĂŻence wastes (biscuits, faĂŻences, 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 faĂŻence 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 faĂŻences are MgO- (5â13 wt.%) and CaO-rich (9â20 wt.%), easily distinguishable from the two French Mg-rich productions of Granges-le-Bourg and LunĂ©ville that we know today. Three samples show high PâOâ
(2.6â3.3 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 20â30 Όm 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 faĂŻences 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 faĂŻences 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 Ă©tĂ© dâĂ©tudier en dĂ©tail les objets archĂ©ologiques mis Ă jour sur le site lacustre de Arbon Bleiche 3, village nĂ©olithique situĂ© sur la rive Sud du lac de Constance (Suisse). Entre 1993 et 1995, le service archĂ©ologique du canton de Thurgovie a fouillĂ© un pĂ©rimĂštre de 1100 m2 (Leuzinger, 2000). La particularitĂ© de ce village est dâavoir Ă©tĂ© occupĂ© pendant une trĂšs courte pĂ©riode (15 ans, entre 3384 et 3370 av. J.-C.), durant la pĂ©riode chronologique qui sĂ©pare la culture de Pfyn (3900- 3600 av. J.-C.) de celle de Horgen (3200-2800 av. J.- C.), pĂ©riode assez mal documentĂ©e en Suisse. La Dr. A. De Capitani a Ă©tudiĂ© le matĂ©riel cĂ©ramique du site. Elle y observe des caractĂšres des traditions Pfyn et Horgen. Les cĂ©ramiques sont classĂ©es dâaprĂšs leur affinitĂ©s typologiques: les pots Ă caractĂ©ristiques Pfyn / Horgen sont sĂ©parĂ©s des formes spĂ©ciales, divisĂ©es en quatre sous-groupes: formes spĂ©ciales Pfyn (caractĂ©ristiques de la culture de Pfyn), formes spĂ©ciales Bayern (en relation avec les cultures de Altheim et Cham de BaviĂšre), formes spĂ©ciales BolerĂĄz (liĂ©es Ă lâĂ©tage BolerĂĄz de la culture de Baden dans la partie ouest du Bassin des Carpates) et les formes spĂ©ciales indĂ©terminĂ©es. De Capitani (2002) propose une origine locale pour les pots Pfyn / Horgen et pour les formes spĂ©ciales Pfyn. Un import de cĂ©ramiques depuis lâAllemagne ou le Bassin des Carpates Ă©tant probable, le but de ce doctorat est dâaffirmer ou dâinfirmer cette hypothĂšse. Les analyses pĂ©trographiques ont tout dâabord permis de sĂ©parer le matĂ©riel non cĂ©ramique (torchis et poids de tisserand) des cĂ©ramiques et des fusaĂŻoles. Le premier groupe est fait dâune argile riche en inclusions et carbonatĂ©e ; le torchis nâĂ©tant pas dĂ©graissĂ©, contrairement au poids de tisserand (dĂ©graissĂ© par de la matiĂšre organique). Les cĂ©ramiques, en revanche, sont formĂ©es dâune argile siliceuse contenant peu dâinclusions et sont dĂ©graissĂ©es. Les cĂ©ramiques ont ensuite Ă©tĂ© sĂ©parĂ©es en 10 groupes pĂ©trographiques diffĂ©rents, en fonction de leur argile et de leur plus important dĂ©graissant (granite, gabbro, rhyolite, chert, chamotte ou os). Ces groupes nâont pas de relation directe avec les groupes typologiques. Les analyses chimiques, quant Ă elles, ont permis de sĂ©parer trois groupes principaux : le matĂ©riel non cĂ©ramique (riche en CaO), les cĂ©ramiques dĂ©graissĂ©es Ă lâos (riches en P2O5) de la grande majoritĂ© des cĂ©ramiques dâArbon Bleiche 3. Du point de vue archĂ©ologique, les pots Pfyn / Horgen sont locaux. La majoritĂ© des cĂ©ramiques ne pouvant pas ĂȘtre sĂ©parĂ©es chimiquement, nous pensons quâelles ont aussi Ă©tĂ© produites localement. Seuls 13 Ă©chantillons sont des exceptions ; ils ne sont donc pas locaux. Malheureusement, leur chimisme ne correspond pas Ă celui des cĂ©ramiques du bassin ouest des Carpates, lieu de production supposĂ© (exception peut-ĂȘtre de un Ă©chantillon). Leur provenance nâa donc pas pu ĂȘtre Ă©lucidĂ©e. Seules les caractĂ©ristiques typologiques des cĂ©ramiques de Arbon Bleiche 3 ont un lien avec la BaviĂšre 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 BolerĂĄz 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 BolerĂĄz were related to the BolerĂĄz 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 SĂšvres Royal Factory soft paste porcelain plate
A Raman study of a SĂšvres 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. 3000â218 BC). Despite this diversity and
long time range, seven of these ware groups, including the âThermi Wareâ, 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 1050â1200 °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. 950â1050 °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 ârefractoryâ clays are obviously better suited to withstand higher firing temperatures and for a longer period than Ca-rich clays