Our new results in the research of smalt, a blue painting pigment popular mainly in the 16^th and the 17^th century, are summarised in a paper published in Archaeological and Anthropological Sciences journal, available to all readers via Open Access:

https://link.springer.com/article/10.1007/s12520-025-02402-4

We have studied mainly historical samples of blue glass melts from the so-called pigment mills and glassworks from the Ore Mts., both on Czech and German sides; for comparison, we focused also on samples from archaeological excavations and, of course, also micro-samples of works of art containing smalt. Thanks to cooperation with German colleagues, we had the opportunity to study a unique sample of bluish glass part of a slag after silver smelting from Schneeberg, which brought a very interesting result: it enabled to solve a long-lasting riddle regarding the source of cobalt for colouring glass before its targeted extraction. The trace admixtures showed that such silver smelting slags were used for this purpose, and they clearly contained, on suitable Ore Mts. localities, sufficient amount of cobalt. Therefore, the glass imported from the Mediterranean area could have started to be replaced by the production from locally available raw materials already in the course of the 13^th century.

Regarding the painting pigment smalt, variable admixtures indicate experimenting with available raw materials in the beginnings of the Ore Mts. production, evident from the glass samples from Soví Huť. On the contrary, elemental composition of smalt from the studied painted works of art is consistent with the production from targeted cobalt extraction (with high amount of arsenic due to extracted cobalt arsenides), whose beginnings has been documented since 1573 in Schneeberg. Therefore, identification of minor and trace elements in smalt can provide one of the useful foundations for dating of painted works of art and of archaeological finds.