Neolithic polished stone of Sammardenchia (Fruili). Petrographic catalogue

Sammardenchia is an important early Neolithic site in northern Italy. It is extremely rich in polished stone with 291 findings consisting of axes, chisels, ornaments, other instruments, pebbles and undetermined fragments, all of which have been studied and which form the basis of the enclosed petrographic catalogue with the essential information relative to each find, the analyses carried out, the texture and mineralogy. The most numerous lithogies are alpine eclogites (36%) and jades or Na-pytoxenites (22.5%) which, together with other high pressure (HP) minor metaphiolites and some paragonite micashicists, usedd for rings, constitute the dominant lithic supergroup (62% of the total), which is evidence of a provenance from the western Italian Alps, similar to the other neolithic sites in northern Italy and Provence. This is a highly structured supergroup, dealth with in various points of the article. A minor supergroup (with acid cinerites/tuffites - 18.5% - and minor sandstones, slates and basalts) represents 22.5% of the lithogies, which are local in origin, from the pebbles of the Fruili plain. A smaller supergroup (10.5%) is represented by metaultramafitic lithologies (serpentines, chloriteschists/fels and nephrites); their provenance is more uncertain and probably diversified. The serpentines are probably partly connected to the HP metaophiolites from the western Alps, and in part from the eastern Alps or Dinarides. The remaining 5% of the materials can be attributed to Carpathian provenance, certain for two silexites and one vitrixc cinerite, less certain and requiring confirmation for a more consistent group of dacites/andesites. The association of these lithologies and some types of artefact forms define the lithic physiognomy of Sammardenchia, which at the moment seems to be unique in Italy. A petrographic summary and a brief discussion is given for all the lithogies, above all from the archeometric aspect. Chemical (XRD and AAS) and minero-chemical analyses by EDS are reported and discussed for a good number of samples. In particular, for the HP metaophiolites a clear distinction was found between the more abundant Fe-ecologites and the less numerous Mg-eclogites, corresponding perfectly with what is geologically known in the western Alps. Among the jades, the Fe-jadeitites (a substantial group here, but not yet known in the literature) seem to be genetically linked to the Fe-eclogites, while a good part of the mixed jades and the omphacitites, probably together with the jadeitites, seem instead to be linked to the Mg-eclogites. The definition of these links is new and must be verified for the archeometric applications and the petrological meaning in future studies.