Raman Characterization of Gemstones from the Collection of the Byzantine & Christian Museum

A very significant component of the collection of gold jewellery in the Byzantine Museum of Athens consists of the Mytilene Treasure from the island of Lesbos. Despite the importance of the Mytilene Treasure, one of the most significant hoards of the 7th century A.D. from the Aegean area, no previous systematic study has been dedicated to it since its discovery in 1951, except for brief entries in exhibition catalogues[Chalkia, 2008]. The presence of Gemstones among the artefacts, set us the question of their mineralogical identity. The samples which we study are the following BXM_875, BXM_872, BXM_178a, BXM_178b, BXM_873a, BXM_873b. The Raman spectroscopy measurements made in the Laboratory of Physicochemical Analysis of Byzantine & Christian Museum. The references on Gemstones in Byzantine literature are many and helpful[Stocchi M.,2009]. Theophrastus of Eressos mentions that exist a kind of false emerald[Caley, 1956]. In Christian Era Epiphanios of Cyprus is described in his text emeralds[Epiphanii Cypri, 4 cent.A.D.]. Another interesting reference is the book of Damigeron (1rst cent. A.D.) which includes a description of emerald[Tahil, 2005]. In Byzantine Era Michael Psellus (11nth c. A.D.) in his text De Virtutibus Lapidorum made a reference on emerald. In accordance to our experimental results: the BXM_872 contains nine real emeralds, the circular amulet BXM_875 is a blue glass with an addition of lapis lazuli, the earrings BXM_178a,b with the blue stones are not sapphires but they are possible a kind of glass paste and the earrings BXM_ 873a,b are green glass.