Diatoms commonly survive pottery firing, and have proved useful in demonstrating the Bell Beaker pottery from coastal Neolithic sites in Holland was made inland by virtue of the fresh water species found in the vessel fabric. The hypothesis that a diatom fingerprint could be used to source pottery is tested here. One difficulty is that clay preparation may damage diatoms, and mixtures of several diatomaceous materials may confuse the analysis. Another problem is damage during sample preparation. Despite these problems, in the Milfield Basin a picture of local manufacture of ceramics from local clay sources does seem to be emerging.