A missing piece of Stonehenge has been returned to the site more than 60 years after it was taken.

A metre-long core from inside one of the prehistoric stones was removed during archaeological excavations in 1958.

Its existence remained largely unknown until 89-year-old Robert Phillips – who was involved in those works – returned the piece after keeping it for six decades.

Mr Phillips, who has since retired to the US, said he wanted to give the artefact back ahead of his 90th birthday.

Now, English Heritage, which looks after the ancient monument in Wiltshire, says analysis of the sample may help establish exactly where the stones originally came from.

Stonehenge: Origins of those who built world-famous monument revealed Show all 6 1 /6 Stonehenge: Origins of those who built world-famous monument revealed Stonehenge: Origins of those who built world-famous monument revealed A new scientific research collaboration is, for the first time, revealing who built Stonehenge. The cutting-edge study sheds a remarkable light on the geographical origins of the Neolithic community that first constructed the ancient site. Complex tests carried out on 25 Neolithic people who were buried at or following the time of the initial construction of the now world-famous monument, have revealed that 10 of them lived nowhere near Stonehenge, but in western Britain, and that half of those 10 potentially came from southwest Wales (where the earliest Stonehenge monoliths came from). AFP/Getty Images Stonehenge: Origins of those who built world-famous monument revealed Three of the cremated cranial fragments used in the study Up until now, it has always been assumed that it was not possible to carry out place-of-origin tests on burned bones – but recent research at Oxford University by Belgian scientist, Dr Christophe Snoeck of the Free University of Brussels, has now discovered that the act of cremation actually crystallises a bone’s structure and prevents the crucial origin-indicating isotope evidence from being contaminated by isotopic signals in the surrounding soil. Christie Willis, UCL Stonehenge: Origins of those who built world-famous monument revealed Aubrey Hole 7 during excavation in 2008 Although the geographically intermediate examples hint at there being a well-worn prehistoric land route between west Wales and Stonehenge, nobody yet knows exactly how the stones (and the cremated remains) were transported. Sea and land routes are both possible. Christie Willis, UCL Stonehenge: Origins of those who built world-famous monument revealed Aubrey Hole 7 following excavation in 2008 Geologically, previous research has shown that the stones (so-called bluestones or dolerite, used for the early phase of Stonehenge) also came from western Britain (in this case, the Preseli mountains in southwest Wales). Archaeological investigations have now pinpointed the quarries they actually came from – and when they were quarried (some time between the 34th and the 32nd century BC). Christie Willis, UCL Stonehenge: Origins of those who built world-famous monument revealed Excavations at one of the recently identified bluestone quarries, at Carn Goedog, Pembrokeshore, west Wales. The recent scientific analysis of the Stonehenge cremated bones (that appear to have been buried adjacent to the newly re-erected stones) is now helping to reveal the origins of the community, which appears to have actually built the earliest version of the monument. It is the strontium and carbon isotopic signatures in the cremated bone material that suggest a western British origin for the 10 individuals – and definitely not from the Stonehenge area. The carbon signal, absorbed into the bones from the timber used in the funerary pyre, also suggests a Western or non-local origin. Adam Stanford, Aerial-Cam Ltd Stonehenge: Origins of those who built world-famous monument revealed The ever-increasing body of evidence suggesting Stonehenge and the original Stonehenge community’s western British origins has substantial implications for our understanding of British prehistory. Christie Willis, UCL

Heather Sebire, the charity’s curator for Stonehenge, said: “The last thing we ever expected was to get a call from someone in America telling us they had a piece of Stonehenge.

“We are very grateful to the Phillips family … Studying the Stonehenge core’s ‘DNA’ could tell us more about where those enormous sarsen stones originated.”

The piece was originally removed during work to raise one of the site’s fallen trilithon – a group of two upright stones with a third across the top.

Cracks were found in one upright as part of this work and it was drilled with three 32mm holes, which then had metal rods inserted into them in a bid to reinforce the stone.

It was one of these thin cones of removed stone which Mr Phillips kept, hanging it first on his office wall in Basingstoke and then taking it with him when he moved to Florida.

His sons Robin and Lewis returned the piece last May, although English Heritage said the find was not announced until Wednesday morning because experts wanted to establish its significance.

Lewis Phillips said: “Our father has always been interested in archaeology and he recognised the huge importance of the piece of the monument in his care. It was his wish that it be returned to Stonehenge.”

Stonehenge’s smaller bluestones are known to have been brought from the Preseli Hills in Wales, but the origin of the much larger sarsen stones remains a mystery.

A project is investigating the chemical composition of these in a bid to pinpoint the source.

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The newly recovered core, which is pristine compared with the weathered stone it was taken from, presents an opportunity to analyse the purer interior of a stone.