Improvements to the analytical protocol of lapis lazuli provenance: first study on Myanmar samples.

The study of lapis lazuli is important to find out information about the provenance of a material used since the Neolithic Age for the manufacturing of precious carved artefacts. The Badakhshan deposits in Afghanistan are commonly considered as the main source of lapis lazuli in ancient times. However, other quarries could have possibly been exploited since antiquity. A protocol to distinguish the provenance of lapis lazuli rocks among four known source areas (located in present-day Afghanistan, Tajikistan, Siberia and Chile) by means of non-invasive techniques was set up in the last years. It is based on differences in the physical-chemical properties measured in 45 lapis lazuli rocks that constitute our reference database. The aim of the present paper is to extend the protocol analysing, by means of a multi-analytical approach, 10 lapis lazuli rock samples, coming from the quarry district of Mandalay in Myanmar, to find out significant petrographic and mineralogical markers. Optical microscopy and scanning electron microscopy were used to perform a detailed petrographic and mineralogical characterisation allowing to distinguish the Myanmar lapis lazuli in three main groups. SEM-EDX analyses on selected mineral phases were performed.