This sample is a fragment of Preseli Bluestone, a type of spotted dolerite, that originated from a quarry in the Preseli Hills of Wales that was determined through petrographic analysis to be the source of the bluestones erected at the prehistoric site of Stonehenge.

Characterized by its distinctive blue-green hue when wet or polished, the dolerite is spotted with white plagioclase feldspar. This specific mineralogical composition, along with textural evidence, helps authenticate its origin, providing a link to Stonehenge’s bluestones, which were transported over 250 kilometers during the Neolithic period.

In the field of archaeology, particularly in Archaeometry and Geoarchaeology, this fragment presents invaluable insights into prehistoric human activity, trade routes, and construction techniques. Additionally, it highlights the understanding of our ancestors of the geologic landscape, reflected in their megalithic architectural feats.