Investigation of artefacts can vary from visual examination, through low-power binocular microscopy and radiography to metallography and full-blown chemical analysis.
Combined visual examination and x-radiography should be used to identify iron artefacts, which often only appear as lumps (Fell et al. 2006). Various typologies have been created for key artefact groups. Examination of the x-radiographs may also reveal some information about methods of manufacture, presence or absence of surface features and/or non-ferrous inlays (Blakelock & McDonnell 2007).
Iron and steel artefacts are best understood through study of their microstructures (Bayley et al. 2001). Metallography shows what types of iron or steel were used, whether it has a composite structure and what treatments it underwent during and after manufacture (Blakelock & McDonnell 2007). An understanding of how metals’ physical properties were manipulated can reveal much about how metals were used and valued in a society.
In an ideal world a proportion of metal artefacts from all excavations should be routinely analysed alongside any production refuse. If this sort of approach is to be adopted, it would be desirable for all developer-funded projects to have funding for analysis of metal-related finds routinely written in (Bayley et al. 2008). The arguments against such a policy are the risk of damage caused by sampling for a quantitative analysis, but the benefits of this analysis outweighs this factor (Blakelock fourthcoming). Analyses of metal artefacts need to be conducted on a sufficiently large scale to be representative; one or two analyses are generally not sufficient to characterize manufacturing practices, an artefact type or culture group (Bayley et al. 2008).