Examination of jet and jet-like material

Staff: Mary Davis [with Duncan Hook (British Museum), Alison Sheridan (National Museums Scotland), Ann Woodward (University of Birmingham)]
Jet necklace from East Kinwhirrie, Angus (Scotland). Image: Helen Jackson for the National Museums of Scotland.
Jet necklace from East Kinwhirrie, Angus (Scotland). Image: Helen Jackson for the National Museums of Scotland.

This work forms part of a wider project, Examination of Ritual and Dress Equipment from British Early Bronze Age Graves (Leverhulme-funded project, led by John Hunter and Ann Woodward (University of Birmingham).

The analysis forms part of the project investigating the nature, use and 'biographies' of Chalcolithic and Early Bronze Age grave goods in England. The correct identification of the raw materials of the artefacts is integral to an understanding of their provenance and significance.

This work takes advantage of a much longer-term project, by Sheridan & Davis, which has been investigating Bronze Age and Neolithic artefacts of jet and jet-like materials from Britain. These materials have been examined both macro-and microscopically, paying special attention to colour, texture and patterns of degradation. These initial examinations give an indication of the range of materials present and have been carried out in conjunction with a range of non-destructive analyses such as XRF, SEM and X-radiography, mostly undertaken at National Museum Scotland and by ourselves.

The British Museum has an extensive range of jet-like artefacts from all over Britain: XRF analysis has been used here to verify initial identifications, particularly in the case of items suspected to have been made of materials other than jet. In addition, the nature of the pale-coloured infill in the Helperthorpe spacer plate pointille decoration has been examined. A trace of white material visible in the bottom of some of the holes was calcium carbonate, and was probably an original, deliberate inlay. Previous analysis of other decorated spacer plates has identified the infills as burnt bone in some cases, and barium sulphate in others. This complements work on infills in other prehistoric artefacts including Beaker pottery, shedding new light on the use of colour in prehistory.