Overview
- An international team led by Professor Duncan Pirrie compared museum fragments of the Altar Stone with field samples and found no geological match in the Orcadian Basin, effectively excluding north‑east Scotland as its source.
- The study used a multi‑technique approach — including sedimentology, petrography, mineralogy, geochemistry and isotopes — to build the most detailed compositional profile of the Altar Stone to date.
- Authors published a refined geological 'fingerprint' that sets specific mineral, texture and chemical criteria for future searches and has already ruled out several other sampled candidate areas.
- Researchers say ruling out regions is constructive progress, with lead authors calling this the most comprehensive investigation so far and stressing that the provenance question remains open.
- Finding the stone’s origin matters for understanding how Neolithic people moved heavy stones and could change views on long‑distance transport and cultural links, so teams will now carry out targeted fieldwork guided by the new fingerprint.