Crucible Fragments Research Articles

Glassmaking remains from the 12th to 14th centuries CE glass workshop in Boshan, Shandong Province, China

Many glass furnaces producing K2O-CaO-SiO2 glass were excavated in Yanshen Town, Zibo city, Shandong province, dating to the Jin to Ming Dynasties, a large-scale glass-making center recorded in historical sources. According to the typological study of ceramics, the workshop which produced the studied samples dated from the Jin to the Yuan Dynasties (12th to 14th centuries CE), and is one of the earliest archaeological glass workshops found in China. The workshop yielded many semi-finished glass fragments, final products, and glass crucible fragments. We conducted chemical and micro-structural analysis by LA-ICP-AES and SEM-EDS, determining that the glass recipe included feldspar, quartz, nitrate, fluorite, colorants, and probably calcite. These minerals match those in the glass recipes recorded in the historical literature. Glass making comprised at least two steps, namely the pre-melting of raw materials into a semi-finished glass, to which more fluxes were then added to make the final glass products or ingots.

Palynological study of archaeometallurgical artefacts from the Late Bronze Age copper smelting sites (Georgia): First results

This article focuses on the palynological (pollen and non-pollen palynomorphs) study of material found with artefacts from Late Bronze Age archaeometallurgical sites in the Lechkhumi area of the mountainous south-west Caucasus region of ancient Colchis. The analysis of organic residues recovered from voids in slag and crucible fragments have revealed an abundance of pollen and spores of diverse plant taxa. Many non-palynological palynomorphs were also found. In total, more than 50 palynomorphs were identified. It was observed that the chemical composition of the copper smelting slag fragments has contributed to the good preservation of the pollen grains, though detailed chemical analyses and experiments are needed. The spectrum from slag includes taxa that are more poorly preserved in sediments, including soil. This preservation undoubtedly makes palynological research of slag residues promising in the future. The range of fossilized plants and spores recovered proves that during the Late Bronze Age in Lechkhumi, forests dominated by chestnut (Castanea sativa) occupied a much larger area than today. Other thermophilic trees, such as zelkva (Zelkova carpinifolia), oak (Quercus), lime (Tilia), and hornbeam (Carpinus betulus) were also present. Thermophilic ferns thrived in the undergrowth as well. In the 13th–9th centuries BC, the existence of warmer climatic conditions in Lechkhumi compared to that we have now is additionally confirmed by the presence of freshwater thermophilic algae Pseudoschizaea, Spirogyra and other Zygnemataceae found in the spectra. Spores of bracken fern (Pteridium aquilinum) and fungus Ustulina most probably reflect felling and human exploitation of the woodland in the close neighbourhood of the site. Comparison of palynological and wood charcoal analyses has demonstrated that the metallurgists of that time used the nearby woods as a source of fuel. Thanks to favourable climatic conditions, beside copper smelting some small-scale agricultural activities were performed which was visible in the composition of herbaceous plant taxa.

Identification of Fazael 2 (4000–3900 BCE) as first lost wax casting workshop in the Chalcolithic Southern Levant

Apart from many lost wax cast metal fragments, crucible fragments and several heated sediment nodules were found at the Chalcolithic site Fazael 2 (central Jordan Valley). Petrographic investigations on the heated sediment nodules revealed many features characteristic of the Chalcolithic Southern Levantine lost wax casting moulds. Heating temperatures were assessed using infrared spectroscopy, showing that casting did not vitrify the clay fraction in the moulds. Consequently, Fazael is the first identified Chalcolithic Southern Levant production site for lost wax cast metal items. These findings confirm the existence of a metallurgical tradition with lost wax casting in the Jordan Valley parallel to the unalloyed copper metallurgy in the Northern Negev. Moreover, crucibles and heated sediment nodules are made of local ferruginous loess, a material not mentioned in previous studies on lost wax casting mould fragments. Therefore, the existence of more than one such production site must be assumed.

ON TRACKS THE POLISSIA EXPEDITION OF 1932: THE NEWEST EXPLORATION OF MINERIES OF 17th—19th century ON THE MALYN REGION

In 2019 the authors conducted an archaeological survey near the city Malyn in the Zhytomyr region. The main task of the work was to find the locations of iron workshops known from historical sources of the 17th—19th centuries as «rudnia». Archival materials of the Poliska expedition of 1932, led by Oleksandr Ogloblin, were used to draw up the survey route. Photographs, location diagrams and descriptions of individual workshops of those studies made it possible to select priority points for a new visit to the sites of ancient industrial complexes.
 A total of 6 locations were surveyed. In their place, it was possible to record a concentration of swamp ore and iron slag, nearby — samples of ceramics, glass and other findings related to the functioning of miners’ villages. Near the humlet Antoniv, on an area of more than 1000 m2, a 3—5 m high slag accumulation was discovered, which was the place of storage of iron production waste from the local «rudnia» on the Voznia River.
 During the exploration several well-known and newly discovered archaeological sites were surveyed, including settlements from the times of Kievan Rus of the 10th—13th centuries near the villages of Nedashky, Ukrainka, Pyrizhky. Many samples of ceramic dishes of the 17th—19th centuries found in Malyn and Pyrizhky. Some of these ceramics have signs of local production. Fragments of tiles were found in some places, in Malyn — samples of ceramic tiles of the 18th (?) century. Near the village Korolivka, a previously unknown site of glass production — guta — was opened. Fragments of crucibles, vitreous mass, slag, ceramics of the 18th—19th centuries were found here. In several places fragments of molded ware, splinters of flint were found, which can be attributed to the Bronze Age (III—II millennia BC) and other eras.
 Near the humlet Antonov the remains of the Roman Catholic church of the end of the 18th (?) century were examined. The building was built by the Polish noblemen Penkowski, who owned a large estate on the Irsha River. Specimens of figured (patterned) brick were taken from this architectural monument. It is important to fix two stone tombstones made of red quartzite in the village Vorsivka near the church. They contain partially legible inscriptions, one of which is dated 1640. These finds testify to the existence in the first half of the 17th century industry of the manufacture of stone tombstones, the place of production of which is located 100 km to the north, in the area of the city of Ovruch, depending on the type of stone.

Ancient metalworking at Yodhawewa site, Sri Lanka: tracing the archaeological and geochemical relationship by analyzing soil and slags

The Yodhawewa archaeometallurgical site was the latest discovery in Sri Lanka in 2018. This study aimed to trace the archaeological and geochemical relationship by analyzing the soil and slags of the site dating back to the c. first to eighth centuries AD. The analysis was mainly based on the X-ray fluorescence (XRF) method. The soil chemistry resulted in some clues to special metal processing zones in the excavation-1 area. The cultural layers of that area (profiles 1 and 2) showed relatively high copper composition (max. 470 ppm), and crucible fragments containing copper particles were also detected in the same layers. The vertical distribution of soil elements and their correlations with TiO2 suggested that long-term metal activity may have affected changes in environmental soil chemistry. Relatively high phosphorus was indicated in the soil-related furnace wall, suggesting the artificial addition of organic matter to the clay body during the furnace wall construction to withstand the high temperatures. High iron slag (HIS) varies from 12.96 to 49.63 wt% of Fe2O3 and shows high MnO, P2O5, and V. Lightweight amorphous/glassy slags (LIS) associated with secondary refining have low iron content and a high CaO and Sr composition.

Traces of Metal Production in the Mezraa Höyük in The Early Bronze Age

Metal objects and findings that suggest metallurgy activities were discovered in the Early Bronze Age architectural layers of the Mezraa Höyük. Among the finds were two crucible fragments and a casting mould. Analysis of the metal fragments preserved on the crucible parts revealed the presence of arsenical copper. Pins with forms that were well known in the Middle Euphrates Region during the Early Bronze Age make up another group of findings. In analysis, one pin was determined to be an arsenical copper alloy and the other a tin-copper alloy. This data proves that metallurgical activities were present in the second half of the Early Bronze Age and that the alloy arsenical copper was produced.

Bronze Production Systems in 6-7 Centuries South Korea: Micro-Structural and Micro-Chemical Analysis of Slags

Metallurgical remains such as crucible, mould, slag and tuyere are generated in the production of bronze. The analysis of slag in particular can be used to identify the raw materials, processes and environments (temperature and condition) employed in the bronze fabrication . The Gwanbuk-ri site in Buyeo is known as the location of a royal palace during the Baekje period, in the 6-7th centuries, and crucible fragments and slags used to make bronze were excavated there. The purpose of this study is to understand the process of bronze production and the origin of the raw ores used in the Baekje period, through micro-structure and microchemical analyses. Using chemical analysis and observation of the microstructure of the crucible and slag samples, we identified evidence of the bronze alloying and melting conditions. The melting process would have taken place under a variable redox atmosphere at 1,100 oC. Cu-Sn-Pb ternary bronze might have been produced by alloying Cu-Sn metal with lead ore (galena) in the Baekje period. The lead isotope composition ratios of 2 bronze slags were located in zone 2 and zone 3 of the lead isotope map in the southern Korean peninsula, which indicates the use of galena from south Chungcheong and north Gyeongsan provinces. For efficiency and cost-effectiveness, a concentrate of lead ore might have been transported from the mine to the consumer site.

Was glass the classical currency of the yoruba?

“The findings from the archaeological excavations at Ile-Ife include several pits that appeared to be furnace ruins, over 20,000 glass beads, 1,500 crucible fragments (ceramic vessels used in glass production), and several kilograms of glass waste. Results of the analysis show that Ile-Ife glass is chemically distinctive. It is now referred to as high lime high alumina (HLHA) glass — Not Known from Anywhere Else in The World” [1].

Materiales metalúrgicos hallados en la ciudad de Ibiza (Islas Baleares)

The analyzes of six samples of slag found during urban development works in the city of Ibiza (Balearic Islands) are presented. These samples, which are one of the first samples of slag analyzed from the old town of Ibiza town, correspond to products from a metallurgical workshop dedicated to the bronze industry. The first three samples to be discussed are remains of ternary bronze metallic elements (copper, tin and lead) in the production phase. These metals would be mixed in ceramic vessels (crucibles), to which the last three samples correspond, which in some cases retain traces of these three elements (copper, tin and lead). These fragments of crucibles are made of clays rich in iron and lime, the addition of which is possibly intentional judging by historical parallels.

Firing up the furnace: New insights on metallurgical practices in the Chalcolithic Southern Levant from a recently discovered copper-smelting workshop at Horvat Beter (Israel)

Recent discoveries at Horvat Beter (Beersheva, Israel) shed new light on the earliest phase of Southern Levantine metallurgy (second half of the 5th millennium BCE). Multiple fragments of furnaces, crucibles and slag were excavated, and found to represent an extensive copper smelting workshop located within a distinct quarter of a settlement. Typological and chemical analyses revealed a two-stage technology (furnace-based primary smelting followed by melting/refining in crucibles), and lead isotope analysis indicated that the ore originated exclusively from Wadi Faynan (MBS Formation), more than 100 km away. These observations strengthen previous suggestions that metallurgy in this region started with furnace-based technology (possibly not locally invented). Furthermore, the absence of any artifact related to the contemporary industry of copper-based alloys indicates a high degree of craft specialization, and together with other regional observations testifies to the important role of metallurgy in the society of the Beer-sheba Valley during this formative time.

Urban Casting Tools as Evidence for Transfer of Technology across the Baltic Sea in 13th- to 17th-Century Estonia

PRESENT-DAY ESTONIA WAS INCORPORATED into the Christian world in the early 13th century. This event brought dramatic changes to both its society and landscape, including the establishment of the first towns that soon played an important role in the emerging Hanseatic network, mediating trade between the West and East. These political and cultural changes are also reflected in the influences that reached Estonian towns, with the migration of craftspeople from German-speaking areas and Scandinavia; in particular, these innovations occurred in non-ferrous casting technology. The most important changes included the introduction of refractory crucibles, massive melting furnaces and more complex stone-casting moulds. Residue analysis showed evidence of highly specialised metalworking taking place. The large sample size revealed some unusual alloys, which are explained either by craftspeople's experimentation or by the reuse of scrap metal. By looking at the different crucible types and mould fragments, we are able to demonstrate how the mobile craftspeople were the carriers of both casting tools and knowledge inside the Hanseatic world.

Ceramic-faience hybrids were used to recycle bronze in North-Western European Iron Age egg-shaped crucibles

We investigated the characteristics of a group of 13 Middle Iron Age egg-shaped crucibles and crucible fragments from Tilburg (The Netherlands). We used a combination of optical and chemical analyses, including hand-held XRF, microCT scanning and 3-D printing polarizing light microscopy and SEM-EDX. The chemical analyses confirmed that the crucibles were used for copper alloy metallurgy. Impressions in the lids of the crucibles turned out to be imprints of copper alloy scrap, including fragments of twisted wire and fibulae. Most remarkable, however, is the large proportion of sheet metal among the scrap.In order to make crucibles from the local, non-refractory clays, a hitherto unknown ceramic-faience hybrid was used: A combination of clay and halophytic plant ash was mixed with silt into a paste, and this was used to construct the crucible. During firing, the flux would promote melting of the clays and probably prevent catastrophic failure of the crucibles. The resulting glassy groundmass – in which silt grains are embedded and partially dissolved – is rich in Al2O3 as well as in Na2O, K2O, CaO, MgO and Fe2O3.It is likely that this technique of crucible manufacture was widespread in Late Prehistory in areas where no refractory clays were available.

Semi-finished glass from Ile-Ife, Nigeria: implications for the archaeology of glass in sub-Saharan Africa

The discovery of glass crucible fragments with the remains of semi-finished glass at Ile-Ife, Nigeria, has provided the first evidence for the existence of autonomous glass production in sub-Saharan Africa.

The Glass Making Crucibles from Ile-Ife, SW Nigeria

Abstract Crucibles to melt glass are very rare in archaeological contexts in sub-Saharan Africa. Recent archaeological excavations at Igbo Olokun, Ile-Ife (Southwest Nigeria) revealed abundant fragments of glass crucibles from 11th-15th century AD deposits, matching the complete and near complete examples earlier reported from Ile-Ife. This paper provides an in-depth examination of these crucible fragments in order to understand the material quality of the crucibles, their typology, and their functions in glass- working/making. Optical microscopic and scanning electron microscopy (SEM) with energy dispersive spectrometry (EDS) analyses were carried out on ten crucible samples. The composition of ceramic fabrics and the adhering glass are presented and discussed in view of their function. The crucibles were produced from specifically selected highly refractory clay and used for melting glass from its raw materials; colorants were added to the melt in the crucible. The useable capacity of the crucibles varied from 1 to 7 liters, equivalent to about 2.5 to 17.5 kg of finished glass for each crucible. Compositional analysis of a sample of the thousands of glass beads from the excavations indicates that the crucibles were used to melt the glass used in the beads. Archaeological evidence of glass bead making at this scale has not previously been reported from West Africa. The crucibles are unique evidence of indigenous glass-working/making in Sub-Saharan Africa from early through mid-second millennium AD.

Heat transfer properties of post-medieval crucibles

In the present case study, the thermal conductivity of two post-medieval crucibles was determined. The investigated crucible fragments represented two broadly contemporary production sites, Grosalmerode and Obernzell, which were employing different types of raw materials (sand tempered kaolinitic clays and natural graphitic clays, respectively) and different firing conditions. The samples were part of a larger assemblage, which had been studied in view of production technology and function of pyrotechnical ceramics in post-medieval Europe and in view of dissemination of products from different production centers. The study results were expected to provide complementary information regarding the technology and use of the crucibles.

El poblado fortificado metalúrgico del Calcolítico Medio y final de Puente de Santa Bárbara (Huércal-Overa, Almería)

The fortified chalcolithic settlement in Puente de Santa Barbara (Huercal-Overa, Almeria), with 1.5 ha, located 3 km away from the Cerro Minado copper mines, and exploited at least during the Late Chalcolithic, presents copper ores, crucible smelting and melting debris such as slags, casting prills, reduction vessels and crucibles. 4% of all the ceramic fragments correspond to reduction vessel and crucible fragments, spatially distributed in the three excavated sectors and suggest the generalization of the metallurgy within the habitat. The percentage of metallurgical evidences could only be compared in the southeast of the Iberian Peninsula to the Copper Age settlements of Parazuelos (Lorca, Murcia) and Agua Amarga (Lorca, Murcia), another minor site of 0.25 ha. These data suggest the hypothesis of small settlements specialized in the production of tools or small metallic ingots made in rectangular crucibles during the Late Chalcolithic in the Southeast of the Iberian Peninsula.

Chemical characterisation of glass waste and crucible fragments from the late 17th - early 18th century Scottish glass manufacturing site at Morison's Haven, East Lothian

Glass waste and crucible fragments from the late 17th – early 18th century Scottish glass furnace at Morison's Haven, East Lothian was characterized using a range of analytical techniques (SEM-EDX, p-XRF, LA-ICP-MS and micro-XRF). Morison's Haven is the earliest excavated glass furnace in Scotland. The glass working waste provides a unique opportunity to compare the actual composition of some of the glass produced with the documentary records of raw materials used at the site and the types of glass artefacts produced. The work provides new technological and economical insights into the nature of glass production in the early 18th century in Scotland.Fourteen samples of glass working waste and three crucible fragments were examined. Two types of mixed alkali glass were found to be produced at the site neither being of a HLLA type as suggested by initial visual analysis. The first was a high quality soda-rich glass made with barilla and a pure sand source. The second type of glass was a range of lower quality mixed alkali glass at least partially fluxed with kelp ashes and using a range and mixture of less pure sand sources. This was most likely used to make windows or lower quality vessels. LA-ICP-MS analysis suggests that sand from two different sources were selected to make the two types of glass.This work is the first attempt to chemically characterize glass waste from a Scottish glass manufacturing site and adds to the known documentary and archaeological evidence to provide more knowledge pertaining to the early glass manufacturing industry in Scotland.

Pre-Columbian metallurgy – Evidence of pyrotechnical ceramics from Rincón Chico, Northwestern Argentina (Andes)

An assemblage of 16 fragments of pyrotechnical ceramics used for metallurgical processing was examined by scanning electron microscopy (SEM). The ceramics came from Rincón Chico in the Andes Region of Northwestern Argentina. They were dated as pre-Hispanic. The examined assemblage comprised seven crucible fragments, five mould fragments, two fragments of so-called perforated crucibles and another two fragments which had not been typologically classified yet. Ten fresh fracture samples were prepared, in order to examine the variation of the degree of vitrification in the ceramics. For comparison subsamples were taken from two fragments and subsequently re-fired under controlled conditions at temperatures between 650°C and 1150°C. In this way the micromorphology observed in the archaeological samples could be linked to equivalent firing (or operation) temperatures. Apart from the fresh fractures 14 polished sections were prepared in order to examine elemental composition and microstructure. These provided information concerning the selection of raw materials, the potential addition of pumicite as temper and the application of bone ash mixed with fine clay as lining. Furthermore, the spot analysis of metal residues provided information about the processed metal.

An Archaic metallurgical workshop in Thasos (Greece): the case of Charitopoulos plot

ABSTRACTAn important archaeometallurgical context dating to the Archaic period (700-480 BC) has been excavated at Thasos (Greece). In particular a pear-shaped metallurgical furnace was revealed while its fill and surrounding area was characterized by the abundant presence of slag, fragments of crucibles and furnace lining. Based on macroscopic examination and instrumental analysis it was shown that the slags and other waste products correspond to the melting and recycling of bronze. The significance of this finding is highlighted by the fact that the workshop is located within the urban core of Thasos. Based on the analytical results it could be suggested that bronze, containing lead was melted and recycled in crucibles at this workshop. Such ternary alloys were mostly used in bronze castings during this period. The results presented here contribute to a better understanding of certain metallurgical practices which were incorporated to the long technological tradition of Thasos.

Gold, Silver and Bronze Analysis of Three Fragments of Technical Ceramic from Elsfleth-Hogenkamp, Germany

Two crucible fragments were found during recent excavations in levels dated to the Roman imperial period in Elsfleth-Hogenkamp, a site interpreted to be a beach market located at the junction of the Hunte and Weser Rivers with water access to the North Sea. The crucible fragments were discovered in cultural layers dated to the 2nd-3rd centuries AD in an excavation trench placed near the concentration of metalworking debris, copper-alloy objects and casting waste found during terestrial metaldetecting surveys. Near this concentration in southwest part of the site, a fragment of technical ceramic with copper-alloy corrosion products was found as a surface find. These three pieces of technical ceramic were investigated by optical and scanning electron microscopy and compared with five pottery sherds of local manufacture. Evidence of the casting of gold, silver, bronze and copper was found as well as the importation of high quality technical ceramic. This study focuses on the material and technical aspects of the metallurgical ceramics and the results raise further questions on the meaning and organization of metalworking at the site.