Scientists have known for many years now that the blue stones, the smaller ones in the outside circles, came from Wales (and the debate on how ancient peoples got the stones from Wales to England's Salisbury Plain still rages in some circles). Recent excavations and testing using cutting-edge technology have revealed that the much larger and perhaps more famous sarsen stones, the tall ones with the horizontal beams on top, came from nearby Wiltshire. But the Altar Stone is something altogether different.

A team of researchers led by Australia's Anthony Clarke, studying at Curtin University, found that the famous 6-ton prone stone contained amounts of apatite, rutile, and zircon and that the mineral profile most closely resembled sandstone found in the Orcadian Basin, a rock formation in northeastern Scotland, some 500 miles away. As with the other giant stones, researchers have no firm theory as to the method of transport or even the motivation for people that long ago to undertake such a journey, said the study's co-leader, Nick Pearce, from Aberystwyth University in Wales. The report confirmed what had been announced in October 2023, that the Altar Stone didn't come from Wales.

As with the other stones, the question of how the Altar Stone got from its source quarry to its destination site remains a mystery. A journey primarily by water, perhaps in boats that hugged the coastline, would have probably taken longer but would have avoided such geographical obstacles as dense forests that stretched over much of what is now England and Scotland. A land journey, on the other hand, could have incorporated water transport in the form of some riverborne methods, the researchers said.