Granito, probably granito di Corsica, from Corsica, France
Geological description:
Coarse-grained granodiorite with megacrysts of pink potash-feldspar, rather smoky quartz, and accessory titanite.
Comments:
This stone is not from Siena. Although similar to granito violetto (marmo Troadense) from Turkey, it is most probably from Corsica, France. This stone was imported by the Medici for use in pietre dure work in renaissance times.