Stonehenge Altar Stone mystery deepens as research reveals it’s not from Orkney

The mysterious origins of Stonehenge’s Altar Stone has deepened as new research has found it did not come from Orkney.

Last month, it was revealed that the massive six-tonne stone at the heart of the monument was brought to Stonehenge from the far north of Scotland, and not Wales, like the monument’s bluestones.

The discovery uncovered that it came from sandstone deposits in an area known as as the Orcadian Basin, which encompasses the isles of Orkeny and Shetland and a coastal strip of Scotland.

It was then assumed by experts that it came from Orkney due to its Neolithic culture with the Ring of Brodgar and Stones of Stenness.

But a new study has found that although the Altar Stone has similar characteristics to Orkney’s monuments, it is not from the same place, meaning the hunt for its origin continues.

The Altar Stone is arguably the most ritually important stone in Stonehenge because it is the rock that marks the intersection of the prehistoric temple’s two most important celestial alignments – the winter solstice sunrise to summer solstice sunset alignment, and the summer solstice sunrise to winter solstice sunset alignment.

The latest study, published in the Journal of Archaeological Science, examined the chemical and mineralogical composition of the stones in Orkney’s two great stone circles – the Stones of Stenness and the Ring of Brodgar – as well as samples of other rocks across Orkney’s islands.

When their X-rays were compared with the Alter Stone, they were found to be markedly different.

The report’s lead author, Richard Bevins, an honorary professor of geography and earth sciences at Aberystwyth University, said Orkney was “the obvious place to look” once initial research some years ago had pointed away from Wales.

He added: “This research is radically changing our thinking about the origins of the Altar Stone. It’s thrilling to know that our chemical analysis and dating work is slowly unlocking this great mystery.”

Due to the size of the Orcadian Basin, experts have warned the origin of the Altar Stone won’t be found quickly, but are determined to “pin down” the location.

While the discovery of the Scottish connection to Stonhenge is exciting, it has lead to more questions than answers. 

This would increase the distance Stonehenge’s rocks have travelled from 120 miles to as far as 700. How or why Neolithic Britons would have moved such a substantial stone this great distance may never be fully revealed.

But it does tell us something about the culture of the period, which spans from Neolithic period to the Bronze age.

The Independent’s archeology correspondent David Keys explains: “The newly discovered Stonehenge-Scotland link, when combined with the Welsh origin of some of the Stonehenge stones, suggests that there might also have been a pan-British aspect to how Neolithic Britons lived.”

Experts still dispute how the stones were transported to the site over long distances, as well as what the purpose of the site was.

However, English Heritage gives the working theory that “the fact that the sun rises over the Heel Stone on the longest day of the year (summer solstice) and sets over it on the shortest day (winter solstice) suggests that it was a prehistoric temple aligned with the sun’s movements.”