A multi-analytical approach for the characterization of powders from the Pompeii archaeological site

Nine black powders found in Pompeii housesin three different types of bronze vessels (cylindricaltheca atramentaria, unguentaries, and aryballoi) werecharacterized in order to assess a correspondence betweenthe composition and the type of vessel and,possibly, to verify if these powders were inks or not.For the compositional characterization, a multi-analyticalapproach was adopted, which involved the use ofscanning electron microscopy–energy dispersive X-ray,Fourier-transformed infrared spectroscopy, Raman, X-raydiffraction, electron paramagnetic resonance spectroscopy,thermogravimetric analysis, gas chromatographycoupled with mass spectrometry (GC/MS), and pyrolysis GC/MS. Powders contained in cylindrical theca atramentariaform a homogeneous group, and their organic andinorganic compositions suggest that they were writinginks, while powders contained in unguentaries andaryballoi could have had several different uses, includingwriting inks and cosmetics. Furthermore, the compositionprofile of the powders found in cylindrical cases showsthat, at 79AD, in Pompeii, carbon-based inks were stillused for writing, and iron gall inks had not beenintroduced yet.