Ongoing LOL projects:
Project: Counterfeit Coins in the Cornell Coin Collection
Description: Olivia Graves (PhD Student, Classics, Cornell) is utilizing the LOL pXRF to determine the surface metal composition of suspected counterfeit coins in the Cornell Coin Collection. Silver coins produced in the Mediterranean world from c. 400-50 BCE were almost purely silver and people typically counterfeited these coins by covering bronze or copper blanks in a thin plating of silver before stamping them and putting them in circulation. Observed green patina and orange rust on the surface of some coins suggests that the collection contains at least a few counterfeits, but the pXRF will provide quantitative data for the surface metal composition of these coins that can then be compared with other XRF studies on coins from the same time period.
Project Coordinator: Olivia Graves
Status: in progress
Project: Pigments on an Egyptian Stele
Description: Alice Clinch (PhD candidate, Classics, Cornell) and Louisa Smieska (Staff Scientist, CHESS) are utilizing the LOL pXRF to conduct pigment analysis on an Egyptian stele fragment from the Cornell Anthropology collection, which has many types of paint visible on the surface. The goal is to use pXRF assays to see how much we can detect about the traces of paint, and compare this with other XRF studies of ancient pigments. The project also includes a thorough point mapping at the CHESS synchrotron beamline in mid March, where they will focus on small portions of the stele. The research will help us to not only identify pigments on the stele but also allow for a comparison of the results between pXRF and the synchrotron beamline to assess the different capabilities of these approaches.
Project Coordinators: Alice Clinch, Louisa Smieska
Status: in progress
Project: Sourcing of Bronze Age Obsidians from the Investigations of Project ArAGATS
Description: Adam T. Smith (Cornell) is utilizing the LOL pXRF to match the geochemistry of archaeologically derived obsidian assemblages from the Tsaghklahovit Plain, Armenia, to a suite of geological sources. The goal is to document shifting exchange networks that positioned the region within a changing set of regional resource flows.
Project Coordinator: Adam T. Smith
Status: in progress
Project: 16th Century Haudenosaunee Copper Objects
Description: Samantha Sanft (PhD candidate, Anthropology, Cornell) is utilizing the LOL pXRF to determine the elemental composition of copper-based artifacts from 16th century AD Haudenosaunee (Iroquois) sites. During this period, Haudenosaunee peoples were acquiring copper from multiple sources. Some of the copper was coming from Europe, in the form of copper kettle fragments; but copper was also coming from the Great Lakes region, in the form of copper nodules. Copper from both North American and European sources seemed to be treated similarly, and was manufactured into similar forms such as tubular beads and other items of personal adornment. Sam uses the LOL pXRF to determine whether the copper objects were manufactured from North American or European copper, providing information on exchange networks in the 16thcentury Northeast. North American copper is distinguished from European copper when a sample has well over 99 percent Cu, with very low levels of trace elements. The artifacts analyzed in Sam’s doctoral dissertation project are housed at research institutions and museums across New York State and Pennsylvania. Research protocols for the pXRF are summarized here.
Project Coordinator: Samantha Sanft
Project: Pigment Analysis of a Late Hellenistic Etruscan Urn from Chiusi
Description: Ryan Stommel (Cornell ’19) and Louisa Smieska (Staff Scientist, CHESS) used the LOL’s pXRF device for nondestructive pigment analysis on a late Hellenistic Etruscan urn from Chiusi in the collection of the Johnson Museum of Art as part of Stommel’s undergraduate honors thesis. Stommel’s thesis was a multi-disciplinary single object study that drew upon four types of evidence and methodologies to study the Etruscan urn. One of these was material properties, for which pXRF was used to analyze the pigments and clay of the urn’s base and lid. The analysis of the terracotta proved inconclusive due to the small sample size and the heterogeneity of the clay. The data gathered on pigments, however, showed evidence for a lack of expensive inorganic pigments. Copper was absent at the spectra for the blue/green hues, which ruled out Egyptian blue, malachite, and azurite. The pigment used to produce this color was the relatively inexpensive green earth. The data from the red points showed a lack of mercury, indicating that cinnabar was not used. Instead the red hues were produced from either red ochre or possibly a mixture including red lead. All of the materials detected on the urn could have been locally sourced for a relatively low cost, which is consistent with the late Hellenistic trend towards lower-cost burial practices at Chiusi among all classes.
Project Coordinator: Ryan Stommel, Louisa Smieska
Project: Ceramic Sourcing and Exchange in Croatia during the Hellenistic Period
Description: This project explores the utility of pXRF for ceramic sourcing studies at the site of Nadin, Croatia. Through a systematic pXRF-based analysis of a collection of Hellenistic relief ceramics this research seeks to identify potential clay source groupings that were accessible to Nadin’s craft networks and thus help to characterize the role of Nadin in the Liburnian regional trade economy. Research protocols for the pXRF are summarized here.
Project Coordinator: Elizabeth Proctor
Project: Pigments on Nazca Ceramics from the Cornell Anthropology Collections
Description: Pending. This study aims to determine whether the cultural changes in Nasca social structure demonstrated through their changing iconography affected the physical production of their ceramics, specifically pigment production. Examining pigment matrices (e.g. homogenous or distinct) will not only determine whether ceramic production techniques were widespread or concentrated, but also their subsequent modes of distribution in the Rio Grande de Nasca Drainage. Using portable X-Ray Fluorescence (pXRF), the pigments of 27 intact polychrome vessels were read and then analyzed using Principle Component Analysis to determine whether compositional changes are concomitant with changes in iconographic phases. The results of this analysis found that though pigments were chemically distinct from eachother, there is not significant variation within individual pigments between different iconographic phases. Research protocols for the pXRF are summarized here.
Project Coordinator: Cristina Stockton-Juarez
Project: Drawing materials in a 17th century Roman portrait by Ottavio Leoni
Description: The study aimed to identify the pigments used in a trois crayons drawing on blue paper of a 17th century Roman noblewoman, held in the Herbert F. Johnson Museum of Art (Angela Gratiani, Ottavio Leoni (1578-1630), 1624, 84.022). Such drawings were typically executed in a limited palette of white, black, and ochre-red chalks, but visual examination suggested the possible presence of additional pigment: a tiny green spot below the sitter’s eyebrow, and a potentially different orange chalk along the sitter’s nose. The green speck proved too small to yield an XRF signal differentiable from the paper substrate. All the red pigments were found to be iron-rich, suggesting an ochre, with no evidence for the presence of multiple red pigments, including vermilion (mercury sulfide) red. The black pigments were all calcium-rich, difficult to distinguish from the calcium content of the paper itself, likely consistent with the use of bone black (calcium phosphate); evidence for black ochre (iron or manganese oxides) was not detected. The white pigments were found to be calcium-rich, consistent with white chalk (calcium carbonate). Traces of lead and zinc where found throughout the drawing, but their association with any of the pigments or with the paper substrate was difficult to clarify. Future work with an imaging measurement such as MA-XRF or multispectral imaging would be useful to further clarify the identities and distribution of pigments.
Project Coordinator: Louisa Smieska, Brittany Rubin
Project: Materials Analysis of Cultural Heritage Objects
Description: Louisa Smieska, a postdoctoral researcher at the Cornell High Energy Synchrotron Source (CHESS) is utilizing the LOL pXRF to examine a range of cultural materials in Cornell collections, including the Johnson Museum and the Rare Manuscripts Collection.
Project Coordinator: Louisa Smieska
Project: Portable X-ray Fluorescence Spectrometer (pXRF) Analysis of Iroquois Copper Artifacts from New York State
Description: pXRF analysis of items of personal adornment including two tubular rolled copper beads along with a third piece of metal, potentially a copper spiral, from an early 16th century Cayuga Iroquois village site located in upstate New York. The results of this research should indicate if the beads were manufactured from native copper or a European copper based metal alloy. The pXRF will also be used to determine if the third ambiguous piece of metal truly is copper.
Project Coordinator: Samantha Sanft
Results: all three items of personal adornment were manufactured from European metals not native copper. One bead was constructed from a copper based metal alloy; the other bead and spiral were both constructed from brass. A full description of the methods, results, and interpretations are included in Sanft’s MA thesis entitled, Beads and Pendants from Indian Fort Road: An Early 16th Century Cayuga Iroquois Site in Tompkins County, New York (Cornell Archaeology).
Project: Medieval Archaeology of the South Caucasus: Ceramic Networks Analysis
Description: The goal of the Ceramic Networks Analysis component of the MASC Project is to compile a baseline comparative compositional dataset for staggered-contemporary Developed Medieval contexts in the Republic of Armenia. Specifically, we are generating a quantitative compositional dataset for ceramic vessel bodies from 11 sites from multiple regions across Armenia, dating from the AD 12th-15th centuries, using the Bruker Tracer III SD portable x-ray fluorescence spectrometer operated by Project ArAGATS and the Landscapes and Objects Laboratory at Cornell University. The goals of this research are: (1) to challenge standing assumptions about the spatiality of production and exchange of ceramics and related commodities in the Developed Medieval period, (2) to establish a database for further qualitative components analysis which will continue to add breadth and depth of our understandings of ceramic production and trade in the Developed Medieval South Caucasus, and (3) to provide a basis for new research questions regarding connections between contemporary sites as well as diachronic ceramic traditions.
Project Coordinator: Kate Franklin and Astghik Babajanyan