Wotton-under-Edge-based engineering giant, Renishaw, is helping scientists discover the secrets of Stonehenge.
It recently assisted a team of geology experts to conduct Raman spectroscopy and minerology on the Altar Stone on-site at the ancient landmark in Wiltshire, using Renishaw's Virsa™ Raman analyser.
The team, headed up by Professor Richard Bevins from Aberystwyth University — who previously confirmed that some of the bluestones at Stonehenge originated from Pembrokshire in Wales — along with Professor Sergio Andò and Dr Marta Barbarano from the University of Milano Bicocca in Italy, hope to discover the provenance of the Altar Stone, which differs in appearance to the other main bluestones at the site.
Professor Andò — who is a researcher in heavy minerals and sedimentology, as well as a Raman spectroscopy expert in geology — had already analysed a small fragment of the Altar Stone at Renishaw's Gloucestershire applications laboratory and was named in a recently published paper which called for the Altar Stone to be declassified as a bluestone, due to it being 'anomalous in its composition, size and weight when compared to the other bluestones'.
Based on his X-ray and Raman microscope analysis of the Altar Stone sample at Renishaw's laboratory, the team believe it did not originate from the Anglo-Welsh basin as first thought, but could have come from northern England or Scotland.
Further Raman analysis is required to confirm the source of the stone, but at six tonnes in weight and partially buried, taking the sample to the lab was out of the question, so the team at Renishaw provided a Virsa™ Raman analyser to use at the ancient heritage site, bringing the lab to the sample instead.
The device allowed for quick movement with micrometre precision; automated Raman imagery with microscopic resolution; focus-tracking technology to keep the probe at optimum focus on an uneven surface; and 11 hours of use due to its low power requirements.
The team were able to acquire Raman spectra from different areas of the Altar Stone and a topographic map of the stone using Renishaw's LiveTrack™ technology, as well as a mineralogic fingerprint and chemical image to help them characterise the stone.
Professor Andò will now carefully analyse all the data, which could pinpoint where the enigmatic stone came from — and help to solve a small part of this ancient mystery.
