Glass Artefacts Research Articles

Identification and Classification of Iridescent Glass Artifacts with XRF and SEM/EDX

Art Nouveau (Tiffany, Loetz) and modern (Jack Ink, Strini Art Glass) iridescent glass fragments were characterized using energy dispersive X-ray fluorescence analysis (EDXRF) and energy dispersive X-ray microanalysis in a scanning electron microscope (SEM/EDX) in combination with factor analysis in order to obtain clustring. A character istic of Tiffany glass fragments is leaded bulk glass, whereas in the case of Loetz K-Ca-Si bulk glass could be determined. Modern glass fragments show a high amount of Na (7 wt% in the bulk of Jack Ink) and 0.6–1.5 wt% Sr in the bulk of Strini Art Glass. The contents of Si and Ca are similar to Loetz glass. Furthermore, the differences in the structure of the glass artifacts could be determined. The cross-sections of Tiffany show a layered structure of the bulk without a specific surface layer whereas the cross-sections of Loetz glass reveal a homogeneous bulk material with one or two homogeneous surface layers in the BE-image. In the case of the Jack Ink a homogeneous bulk glass and an inhomogeneous multilayered surface could be determined. Strini Art Glass show a homogeneous bulk glass and a homogeneous surface layer in the backscattered electron image.

‘Nowadays with glass’: regional variation in Aboriginal bottle glass artefacts from Western Australia

AbstractThis paper builds on the few well known analyses of glass artefacts by recognising that bottle shape strongly influences glass artefact morphology in glass tool manufacture. Analysis of Aboriginally worked glass artefacts, using similar bottles, from two regions in Western Australia show differences that cannot be attributed to regional variation in raw materials. These differences may relate to long term approaches to artefact manufacture.

Faunal Remains in California Condor Nest Caves

Abstract Studies of faunal remains in California Condor (Gymnogyps californianus) nests in the 1980s yielded bones and hair of a variety of small, medium-sized, and large mammals, and a near absence of avian and reptilian materials. A prevalence of small to medium-sized species may reflect ease of penetration of hides of such carrion and a relative abundance of ingestible bone from such species. Remains also included metal, plastic, and glass artifacts, likely mistaken for bone materials by condors. Size distributions of bone materials and percentage artifacts among hard remains suggest an overall absence of severe calcium-supply problems for condors.

FAUNAL REMAINS IN CALIFORNIA CONDOR NEST CAVES

Abstract Studies of faunal remains in California Condor (Gymnogyps californianus) nests in the 1980s yielded bones and hair of a variety of small, medium-sized, and large mammals, and a near absence of avian and reptilian materials. A prevalence of small to medium-sized species may reflect ease of penetration of hides of such carrion and a relative abundance of ingestible bone from such species. Remains also included metal, plastic, and glass artifacts, likely mistaken for bone materials by condors. Size distributions of bone materials and percentage artifacts among hard remains suggest an overall absence of severe calcium-supply problems for condors.

Water, Water Everywhere: Collections Management for Wet Sites

Digging a wet site (wells, privies, and other waterlogged contexts) can present a logistical challenge to field directors. But what happens once the artifacts come into the lab? All archaeologists know that wet organic artifacts should be kept wet, but then what? And what about ceramics, glass, and other inorganic artifacts? Does slow-drying mean more than drying something slowly? When can all those wet artifacts come out of the water to be labeled and cross-mended? This paper presents lessons learned from the recent excavation of a Civil War privy and some practical guidelines for managing collections from wet sites so as to promote their long-term preservation. A lab manager teamed with an archaeological conservator to develop easy-to-follow procedures which are being followed by a largely volunteer work force.

A late 18th-century inn clearance assemblage from Uxbridge, Middlesex

Numerous large, well-dated 18th- to 19th-century closed assemblages of domestic pottery, glass and other artefacts have recently been excavated in the London area. Discarded as a single deposit, these ‘clearance groups’ offer an invaluable opportunity to compare individual establishments across the social spectrum, allowing the evolving role of ceramics in a rapidly developing consumer society to be traced. This article is concerned particularly with clearances from inns and taverns, focusing on a fine assemblage of pottery, glass and clay pipes from the site of the King’s Arms in Uxbridge, deposited c. 1785–1800. The range of finds recovered, their sources and function, and their contribution to our understanding of inn society are discussed and comparison is made with clearances from other victualling establishments and households in London, Guildford, Leicester and the American colonies, examining in particular the availability of ceramics, choice, taste, social status and function, as demonstrated by archaeologically recovered collections assembled by their original owners rather than by the preferences of modern curators and collectors.

Considerations of Hydration-rind Dating of Glass Artefacts: Alteration Morphologies and Experimental Evidence of Hydrogeochemical Soil-zone Pore Water Control

SEM-EDAX textural-chemical alteration morphologies of man-made glass from Egypt and modern soda lime glass are compared to literature data for obsidian and sideromelane (rhyolitic and basaltic glass).A series of laboratory experiments using soda lime glass slides held at 90°C for 3–21 days in baths using different salt solutions (MgCl2, LiCl, NaCl, CaCl2and KCl) in various concentrations provides compelling evidence that for any particular glass composition the style of glass corrosion (hydration–dissolution) is dependent on solution geochemistry. Two fundamental styles of glass corrosion occur: pitting dissolution, and gel-lamination hydration. Glasses of different compositions may behave differently in similar anthrosols. Reaction style and kinetics, and hydration–dissolution rates are controlled by soil temperature, glass and soil water geochemistry, and ultimately alkali exchange between the glass artefact and the soil-zone pore water.Glass and gel thickness loss through dissolution reactions may compromise hydration dating and may be responsible for a variety of reported apparent chronological inconsistencies. Future studies with obsidian and sideromelane under bath conditions and in the natural environment are needed to assess their response to variable soil-zone solution geochemistry.

HF plasma pencil — new source for plasma surface processing

The high-frequency plasma pencil is a source of a highly active environment (electrons, ions, reactive radicals, excited atoms and molecules), which can be generated at atmospheric, reduced or increased pressure, preserving a broad control of performance. As an active medium flowing through the plasma jet a gas, a liquid as well as a mixture of dispersed particles (powders) can be used. The plasma jet can be controlled like hand-operated tools. Several technological applications have already been used (restoration of archeological glass artifacts, fullerene production, fragmentation of molecules for microelectrophoresis, plasma polymerization in liquids, various plasma surface treatments, etc.).

The Failure of Obsidian Hydration Dating: Sources, Implications, and New Directions

Obsidian hydration dating (OHD) originally promised to be a rapid, inexpensive, simple and reliable method for dating obsidian artefacts. The perceived elegance of OHD resulted in rapid acceptance and widespread application despite questions concerning its theoretical rigor. With increased usage it has become evident that, while economical, simple and fast, OHD is unreliable. Here results of a secondary ion mass spectrometry (SIMS) study of obsidian and synthetic glass artefacts are presented that explain why OHD has not lived up to expectations. The results suggest that the standard OHD equations are inappropriate and that traditional optical measurements are inherently flawed. Although significant refinement will be needed, the results suggest that both chronological and palaeoclimatic data might be obtained from glass hydration rims through an improved analytical methodology and more rigorous treatment of the data.

The use of SSNTDS in the retrospective assessment of radon exposure in high radon rural communities in Yugoslavia

A description is given of the field application of a technique using CR-39 and LR 115 detectors to determine alpha recoil implanted 210Po surface activity on domestic glass artefacts in dwellings. These investigations took place in two small stable rural communities in uraniferous areas of Yugoslavia where between 32% and 74% of contemporary indoor radon levels were found to be above the commonly used Action Level of 200 Bq m −3 and individual levels as high as 8700 Bq m −3 were measured. The 210Po data is used to retrospectively estimate radon exposures in these communities. Comparisons between the retrospectively estimated radon exposures and those being received at present are made.

PLASMA-LIQUID TECHNOLOGIES FOR TREATMENT OF ARCHAELOGICAL ARTIFACTS

Plasma-liquid technologies at atmospheric pressure provide a wide range of possibilities for applications. One of them, the treatment of archaeological artifacts, is presented in this paper. The effects of discharges between a metal electrode and a solution surface and/or an interaction of hollow cathode plasma jet, plasma pencil, with liquid on the corroded surface of bronze and glass artifacts were studied. It was compared with standard low pressure plasma techniques and with the effects of electrolysis. Original and treated objects were characterized by means of scanning electron microscope (SEM) with energy dispersive analyser used for the spot elemental analyses.

Post-European Aboriginal Occupation Of The Southern Curtis Coast, Central Queensland

The key findings during test excavation of the Ironbank Site Complex have revealed a post-European Aboriginal occupation of the Southern Curtis Coast, Central Queensland. Identification of starch grains adhering to the surface of glass artefacts also illustrates the potential of residue techniques in the study of contact period materials.

FT-Raman Spectroscopic Study of Decorated Stained Glass

Two samples of decorated stained glass (14th century and 19th century) from Southwell Minster, Nottinghamshire, U.K. have been examined with the use of Fourier transform (FT)-Raman spectroscopy. The pigment used in both cases has been identified as red ochre, and the potential application of FT-Raman spectroscopy to an important area of conservation and restoration of glass artifacts is demonstrated.

Glass of the past: The degradation and deterioration of medieval glass artifacts

Medieval artifacts made of glass are at a serious disadvantage concerning the chemical stability compared with ancient or common modern glasses. The total amount of silica and other network formers such as alumina is very low and potassium instead of sodium was introduced into the silicate structure by using local raw material. By means of scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS) and nuclear reaction analysis (NRA) a weathering mechanism governed by an ion exchange process could be determined for medieval glass paintings exposed to the ambient air for centuries. Additionally, the leached glass surface of medieval hollow glass artifacts found in a well and exposed to moist earth show a brown discoloring due to the oxidation of Mn(II) to Mn(IV) oxide. That process can be converted by a treatment of the glass objects in an aqueous hydrazine solution.

Grouping Glass Artefacts by Specific Gravity and Refractive Index Measurements

Grouping Glass Artefacts by Specific Gravity and Refractive Index Measurements

Sources and sourcing of volcanic glass in Hawai'i: implications for exchange studies

AbstractThe role of exchange in Hawaiian prehistory has received only minimal attention despite Hawai'i being one of the most highly stratified societies in Oceania. This paper demonstrates the utility of provenance studies of volcanic glass as a means of providing an empirical grounding to addressing exchange and interaction in Hawaiian prehistory. Volcanic glass studies in Hawaiian archaeology are reviewed, geologic sources of the material described. and a geologically‐based model formulated to guide the discovery of volcanic glass sources on West Moloka'i, Hawaiian Islands. The results of a 19.000 hectare survey are reported and the first two sources of volcanic glass on Moloka'i are described. Using an electron microprobe, the geochemical similarity of source material and volcanic glass artifacts from distant habitation sites is demonstrated. It is concluded that sources of volcanic glass can be discovered in a systematic way; microprobe analysis is a good technique for geochemical characterization; and, with additional work, hypotheses of exchange and interaction in Hawaiian prehistory can be tested with a systematically collected, empirical data base.

Investigation of the origin of archaeological glass artefacts by means of pattern recognition

The origin of medieval glass artefacts is studied by using a supervised learning technique, which is shown to be helpful when samples cannot be identified by typical design and appearance. A set of seventy pieces of glass was analyzed for ten trace elements by optical emission spectrography. The data matrix of 33 known objects from five origins was evaluated by multivariate variance and discriminant analysis in a training step. The extracted non-elementary discriminant functions were used to classify the 37 unidentified samples. The classification result is discussed in terms of its cultural/historical information content.

Archaeological Testing and Preliminary Archival Investigations of the Ruben Hancock Site, 41TV875 Travis County, Texas

The Ruben Hancock Site (41TV875) is located at a position on the centerline of the extension of Parmer Lane from FM 1325 (Burnet Road) to FM 620. The site was found during a survey of the right-of-way conducted by the author on the 9th of August, 1984. Other sites were found during the survey but were too ephemeral or too disturbed to warrant further investigation. It was judged at the time of the survey that the Ruben Hancock Site, because of its disturbed condition and the presence of metal and glass artifacts, warranted further investigation. It was suggested that the testing consist of a metal detector survey.

Oyster Cove: Archaeological traces of the last Tasmanians and notes on the criteria for the authentication of flaked glass artefacts

Stone, bottle glass and pottery artefacts occur at the Oyster Cove Aboriginal Station, occupied from 1847 to 1869. Criteria are advanced for recognition as artefacts of bottle glass fragments.

MAYAN OBSIDIAN: SOURCE CORRELATION FOR SOUTHERN BELIZE ARTIFACTS

High‐precision neutron activation measurements have been made on mesoamerican obsidian from Ixtepeque and El Chayal which are thought to be the major sources of volcanic glass artifacts in pre‐Columbian times. These results are compared with measurements on obsidian artifacts from Lubaantun, Wild Cane Cay, Frenchman's Cay and Moho Cay.