In 2013, Dr. Earle McBride, a researcher studying sandstone diagenesis and the textual and compositional maturation of sand during transportation, mixed samples collected from Omaha Beach in 1988 with a blue epoxy, creating an "artificial sandstone", before slicing it into thin sections. Utilising an optical microscope and an external light source, shiny, opaque grains could be identified. Although wave action had elicited rounding on the edges of some coarser grains, the shard-like angularity and corrosion of both coarse and fine grains suggested these grains were man-made. It is believed that the roughness of said grains was imparted by microporous surfaces produced during production and corrosion products post-explosion.
This inspection, alongside tests revealing that the grains were magnetic, led McBride to conclude these grains were pieces of shrapnel.