A heavily concreted iron bolt or nail, with plate washer attached. ‘Concretion’ occurs when iron oxide (rust) spreads from an iron object submerged in water, and gathers other items such as sand, small stones, seawater chlorides and even sea life into a hard shell around the original object. All of these can be seen attached to this 6 inch bolt, found on a beach in the North East of England. Given enough time the original subject can entirely convert to oxide, leaving a void inside which can then be examined using an X-ray machine. In this case, the bolt has not been submerged for a very long time, and may also be cast iron which helps slow the rate of conversion. Concreted artefacts can be delicate, so breaking them open should only be attempted by conservators. Trapped chlorides will need to be removed carefully to prevent their expansion in dry air, damaging the artefact.
This object was scanned as an experiment with turntables and fixed camera postions. 117 images, processed in Metashape.
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