This paper presents the scientific investigation of three Lemnian sphragides (terra sigillata, stamped earth), a famed medicinal clay in antiquity, dated to the sixteenth–seventeenth centuries, and presently in the Museum for the History of Pharmacy, University of Basel. The three specimens are compared with clays from the purported locality of its extraction, at Kotsinas, NE Lemnos, Greece. The study suggests a local origin for the Basel samples; it also demonstrates, for the first time, that the three Lemnian sphragides have a significant antibacterial effect against Staphylococcus aureus, a common Gram-positive pathogen, but have no such effect against Pseudomonas aeruginosa, a Gram-negative microorganism. Clay samples from the purported locality of extraction showed no antibacterial effect against S. aureus. Subsequent analysis with ultra-performance liquid-chromatography mass spectrometry (UPLC-MS) revealed the presence of organic constituents in one sphragis which were absent from a sample of modern clay. A fungal secondary metabolite is proposed here as the active ingredient but other factors may also play a role. The ongoing investigation into the bioactivity of some medicinal clays might aid in the re-evaluation of Belon's statement included at the start of this paper, namely, that the Lemnian earth worked only because people in the past wished it to work.

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Current technical interest in the nature of the black inlaid decoration on ancient metalware has stimulated an examination of some of the well-known bronze daggers, silver vessels, and other fragments, all with inlaid decoration and dating to the 16–14th centuries BC, from Mycenae, Prosymna, Dendra, Routsi, and Pylos. Results of non-destructive X-ray fluorescence analysis point to great versatility in working with copper (or bronze)–gold–silver alloys. The black inlaid decoration is usually copper/bronze–gold alloy with small quantities of silver. Four of the objects were also examined by X-ray radiography.

The industrial minerals (IM) of antiquity, the ‘earths’ of the Classical sources, have for long eluded the archaeological record because of the limited material evidence they leave behind in the course of their extraction and processing. The extensive references in Classical and medieval literature and travellers' accounts have never previously been followed up by detailed surveys and by scientific analysis. In the course of April–May 1998 archaeological, topographic and geological surveys were carried out at the Roman site of Aghia Kyriaki, on the island of Melos, with the long term aim of putting the elusive ‘earths’ on the archaeological map of ancient industries. The present article outlines the work so far and highlights the complex factors that may contribute to the identification and characterisation of industrial minerals working in the absence of pyrotechnological waste. Furthermore, since IM processing requires a sustainable low temperature energy source, the hypothesis is put forward that Aghia Kyriaki may have been built on agriculturally inhospitable terrain mainly in order to take advantage of the area's still active geothermal field. If proven, this may constitute evidence for the first use of a ‘soft’ and environmentally friendly energy source during the Roman period in the Aegean.