Located in the northern part of the site, even the aftermath of Structure K is an important part of the story of the site.
There are the impressive remains of an episode of metalworking that includes furnaces, anvils, whetstones, bronze waste, splashes and droplets, crucibles, and, very significantly, moulds for casting fine, bronze jewellery.
Over sixty moulds and mould fragments have been recovered. These were used to cast a variety of objects ranging from simple bronze rings, to distinctive decorated dress pins, called “projecting ring-headed pins”, and penannular brooches, which are the lovely open-ring, cloak brooches that are sometimes referred to as “Celtic” brooches.
The volume and nature of the items being produced suggests that this was a socially significant collection of prestigious items aimed at denoting the identity, and status of those who were to wear the items as badges of their belonging and importance within the community.
Importantly, it is the entire suite of materials found together, as well as their precise distribution pattern within the trench, that indicates strongly that this material relates to an in-situ metalworking event, rather than a secondary event, such as merely the refuse disposal of old moulds, or even their ritual deposition.
This is important because the closer we can get to the actual context of the metalworking events the clearer and more direct our picture of the process becomes.
The moulds for casting the bronze jewellery were found in an area several metres in diameter, scattered within and across the remains of Structure K that was already ruinous and unroofed by the time the metalworking was happening.
That building was itself found to overly the partially in-filled remains of a large enclosure ditch that had originally surrounded the broch period settlement. Radiocarbon dates show that the jewellery-making occurred sometime between the AD240s and the mid AD300s. This places the metalworking very definitively after the end of the broch.
The understanding of the chronological and structural context of the metalworking allows us to consider the social context of this episode of metalworking. It is happening at a period of quite dramatic change in the material circumstances of Northern Iron Age communities in Scotland, at the end of the conventional Middle Iron Age and the beginning of the Later Iron Age periods, and contemporary with the mid to later Roman period further south.
Very interestingly, we can therefore say that this episode occurred after the culmination of the monumental phase of the site – after the demise of the massive broch at the heart of the community.
One prominent British Iron Age scholar (Professor Niall Sharples from Cardiff University) has previously suggested that across Atlantic Scotland a pattern can be observed in which, around the time of the end of the brochs, when monumental domestic architecture is on the wane, there is a very substantial rise in the volume of items that reflect the presentation of the individual through personal adornment. This phenomenon seems to be reflected at The Cairns also.