Object: Unidentified Object (Bronze Age)
Period: Bronze Age to BRONZE AGE ( to )
Material: Gold 
Found: Grosmont, Monmouthshire, Monmouthshire (Wales)
Discovery method: Metal detector
Length: 12.7 mm
Thickness: 2.8 mm
Weight: 2.37 g
Description: Probable Bronze Age gold strip fragment.



This is a semi-worked thickened strip fragment of gold of broadly rectangular shape. The strip has been worked and there are hammer facets visible on the flat surfaces and side margins. One edge has been hammered up and has a projecting margin on one face edge. The strip was broken at one end with a double-grip tool without sharp edges. As a result, there is widening, lateral distortion with thinning at one end, near the break. On one face, the break has created a near flat angled facet, while on the reverse there is a distinct concave curvature of the break, where gripped. The opposite end looks to have been snapped, rather than pulled, the break edge being irregular and with no thinning and minimal distortion of shape evident. Projecting burrs on the face edges look to have been hammered down. On one face, there is a linear crack evident in the metal along the axis of the strip, while a second smaller area of surface cracking is also evident. The gold has a yellowish tinge, rather than tending toward silver or having an orange hue.



Dimensions: maximum length 12.7mm; maximum width 8.5mm; maximum thickness 2.8mm; weight 2.37g.
Notes: Metallurgical analysis (Mary Davis)



Method



Semi-quantitative surface analysis of the gold strip was undertaken for the gold, silver and copper content of the gold fragment. This was achieved using a Bruker TRACeR III-SD hand-held X-ray fluorescent spectrometer (HH-XRF) with a rhodium tube, and a titanium/aluminium filter. The readings were taken at 40 kV and 9.6µA for 100 live seconds.

Surface analysis is susceptible to distortions due to the asymmetry of whole objects (rather that flat polished samples). Surface corrosion can lead to the surface enrichment (e.g. tin) and depletion (e.g. zinc) of elements.



Results



Three spectra were taken of the object, which was found not to be particularly homogeneous in composition, and the overall results averaged:

Gold: 85-87%;

Silver: 10-12%

Copper: 2-2.5%



Interpretation



The amount of copper and silver present in the gold fragment is consistent with a typical Bronze Age composition. The results sit within the known range of compositions of gold objects from Wales of either Middle or Late Bronze Age date (e.g. Gwilt et al 2005, 36 & Fig. 4).



Identification & discussion (Adam Gwilt)



As a fragment of semi-worked gold, it is not possible to identify this with certainty to a class of finished gold artefact type of known period or date. The hammering and working technique observed on this fragment (see above description) is consistent with observed Bronze Age working technology, however is not, in itself, diagnostic to a particular date.

In this instance, it is the metallurgical analysis of the composition of this gold fragment which provides the most instructive evidence as to the possible age of this object. The high, but not refined gold content in this strip fragment, in the range of 85-87% gold and with 10-12% silver content is consistent with known Bronze Age gold compositions, to some degree reflecting the natural incidence of silver within alluvial gold ores. Copper was deliberately added to gold alloys in the Bronze Age, with the general trend for increasing proportions of copper with time, Late Bronze Age artefacts generally containing 4-10% copper and Early Bronze Age gold generally with less than 1% copper content (e.g. Hartmann 1980; Northover 1993, 517, Fig. 2). This strip, containing 2.0-2.5% copper sits in the overlap zone with other gold artefacts dating to the Middle and Late Bronze Age (Gwilt et al 2005, 36 & Fig. 4). Typically, Roman gold is highly refined, with the silver and copper content removed, giving the metal a more reddish colour.



Part-worked or re-worked fragments of Bronze Age gold are sometimes discovered, as single finds or as elements within hoards (e.g. Green 1983; Green & Northover 1996; Gwilt et al 2005; DCMS 2004, 19, Cat. & Fig. 11; DCMS 2007, 22-3, 26, & 39, Cats. & Figs. 5, 7, 17 & 25; British Museum 2008, 22 & 24, 273-5, Cats. & Figs. 27, 33 & 34). Their occurrence as single finds has been increasing in recent years, as better levels of reporting treasure finds have been achieved through the Portable Antiquities Scheme in England and Wales. Therefore, the possibility of this strip being a single find of Bronze Age date is also consistent with a wider reported pattern.



A preliminary search of the Heritage Environment Record for Monmouthshire has indicated there are no known Bronze Age or prehistoric sites in the immediate landscape vicinity of the find-spot.



Authors



Adam Gwilt - Principal Curator: Prehistory, Department of History & Archaeology, Amgueddfa Cymru - National Museum Wales



Mary Davis - Formerly Principal Analytical Services Officer, Department of Collections Services, Amgueddfa Cymru - National Museum Wales



References



British Museum 2008. Treasure Annual Report 2005/6, London: British Museum / Department for Culture, Media and Sport.



DCMS 2002. The Treasure Act 1996; Code of Practice (Revised); England & Wales, London: Department for Culture, Media and Sport.



DCMS 2004. Treasure Annual Report 2003, London: Department for Culture, Media and Sport.



DCMS 2007. Treasure Annual Report 2004, London: Department for Culture, Media and Sport.



Green, H.S. 1983 Exhibits at ballots: A Late Bronze Age gold hoard from Llanarmon-yn-Iâl, Clwyd, Antiquaries Journal 63, 384-7.



Green, S.A. & Northover, J.P. 1996. Note: Recent Finds of Late Bronze Age Gold from South Wales, Antiquaries Journal 76, 223-8.



Gwilt, A., Kucharski, K., Silvester, R. & Davis, M. 2005. A Late Bronze Age Hoard from Trevalyn Farm, Rossett, Wrexham; With Some Observations on Hoarding Practice and Gold Bracelet Weights, Studia Celtica 39, 27-61.



Hartmann, A. 1980. Appendix 3; Analyses by A. Hartmann of British Prehistoric Gold and Some British Ores, In J.J. Taylor, Bronze Age Goldwork of the British Isles, Cambridge: Cambridge University Press, 138-41.



Northover, J.P. 1993. Bronze Age Gold in Britain, In G. Morteani & J.P. Northover (eds.), Prehistoric Gold in Europe; Mines, Metallurgy and Manufacture, London: Kluwer Academic Publishers, 515-31.
Subsequent action: Acquired by museum after being declared Treasure