Characterization of lapis lazuli from different provenances by means of micro-Raman spectroscopy

Lapis lazuli is a blue semi-precious stone widely used since the antiquity for the manufacture of precious objects and jewellery. It’s characterized by the presence of the mineral lazurite, giving the typical blue colour to the rock, traversed by gray-white or yellowish veins, due to the presence of various accessory minerals such as calcite, wollastonite, phlogopite, plagioclase, diopside and others.There are few quarries of lapis lazuli in the world, and only some of them could be used since 7000 years ago. In particular the Afghan mines in the Badakhshan region have been considered for long time as the only source of lapis lazuli already exploited to provide the raw material to ancient civilization of Mesopotamia, Egypt, Indus Valley and China. In more recent times also other sources have been taken in consideration: Pamir mountains (Lyadzhuar Dara, Tajikistan), Pakistan (Chagai Hills) , Siberia (Irkutsk, near Lake Baikal) and others not yet geologically confirmed. Despite the knowledge of the provenances of the raw material can help reconstructing trade routes of the past, a systematic and exhaustive provenance study of the raw material utilized in artworks is still lacking.