Chemical investigations suggest that raw material for Ireland’s prehistoric gold hoard may have been sourced from near neighbours. An alternative explanation is that there are forgotten Irish deposits rich in gold. Visit the National Museum on Kildare Street, Dublin, and you will be struck by the sheer number of gold objects. The desire for this precious metal was strong in prehistoric, pagan Ireland. The array of gold ornaments includes collars, torcs and bracelets, mostly from the Bronze Age, 2,200 to 800 BC.
“It is highly significant in European terms and disproportionately large given the size of the country,” says Mary Cahill, curator of the museum’s Bronze Age collection. Yet Ireland is not renowned for its gold deposits, so where this gold came from has puzzled archaeologists.
Rob Chapman has spent hours standing in ice-cold streams and rivers across Ireland panning for gold. A geologist at Leeds University, he got the gold bug working in a South African mine. He helped collect natural gold grains from across Ireland to compare to the museum gold.
Natural gold is usually found as a mixture, with silver often the main alloying metal. Chapman cross-checked silver content in natural gold with artefacts from the early Bronze Age, 2,200 to 1,800 BC. The gold is consistent and seems to come from one area, possibly from river gravels. The artefacts themselves are mostly crescent-shaped collars (lanulae) and sun disks, decorative objects possibly for clothing or for embellishing wood or stones.
“Jewellery is not an appropriate term for these things,” says Cahill. They were regalia, in the sense a modern king or queen might wear, or tied to religious ceremonies. Goldsmiths confined themselves to producing particular objects, presumably for an elite class, and certain motifs recur which archaeologists believe concern the power of the sun and fertility.
Chemical analysis revealed silver at 10 per cent, which, combined with trace amounts of tin and copper, indicated the Mourne Mountains as the most likely source of these objects. “Nothing else seemed to fit this early Bronze Age stuff,” Chapman explains.
But advances in geochemistry recently allowed Chris Standish, an archaeology PhD student in Bristol University, to characterise Irish native gold and museum gold using variations in the four natural types of lead atoms, or lead isotopes. The quantities of lead are tiny, around 0.002 per cent, and were measured using a mass spectrometer.
“We couldn’t find a match between any of the Irish gold deposits,” Standish says, having examined likely areas, including the Mournes and Croagh Patrick. The lead isotope signature of the museum gold was closest to the gold deposits of Counties Wicklow, Wexford and Waterford.
“Looking purely at the lead isotopes, gold in the artefacts is most consistent with gold from the southeast,” says Standish. But there is too little silver and trace metal for it to be a proper match.
Standish suggests there may be gold he has yet to analyse, but another, controversial, explanation is gold imports. According to Chapman, “The lead signature he [Standish] gained from the early Bronze Age artefacts corresponded to the granite rocks in Cornwall,” which he says has irritated some archaeologists.
Cahill is waiting for further detail to emerge, but says there is no supporting archaeological evidence for extensive gold imports to Ireland at this time. “We know that Irish copper and bronze objects turn up in Britain,” but there are no signs of gold coming in. And clues pointing to southern Britain as a source for Irish gold are not conclusive.
“Natural gold does occur in Cornwall, but it is difficult to find and we cannot say categorically whether the gold content is compatible or not,” says Chapman. Since the early Bronze Age, the land has changed so much that you cannot visit the same sites available to the Bronze Age people; some lie underwater.
One other explanation is a deposit of gold which has eluded modern prospectors but was used by Bronze Age people. Given extensive gold exploration in Ireland since the 1980s, a hidden source is somewhat unlikely, say geologists, dimming hopes of a Celtic El Dorado. But it’s a possibility.
Peruse the Bronze Age gold collection at the National Museum. See museum.ie