The rarity of pyrite in the Breckland region is supported by extensive lithological studies of the regional Pleistocene geology. Analysis of over 121,000 individual clasts from 26 sites, including pre-Anglian fluvial gravels, Anglian glacial sediments and post-Anglian fluvial gravels, provides a robust dataset, with more than 33,000 clasts specifically from the Barnham area (Supplementary Information, section
3). None of the samples contained pyrite fragments, demonstrating the extreme rarity of this mineral in Pleistocene deposits in the region.