A non-invasive time-of-flight neutron diffraction (TOF-ND) analysis has been performed on archaeological pottery fragments from the excavation sites in the "Strait of Messina'' area (Sicily, Southern Italy). The revealed quantitative information on the mineralogical composition have been compared, in the case of two samples representative of coarse and fine grained pottery, with the weight fractions of the crystalline phases as obtained from X-ray diffraction on powders (XRPD), for different amounts of extracted powder. From the results, the consistency of these micro-destructive and non-invasive approaches has been checked. This research may contribute to better define the most efficient sampling and analytical method for the determination of mineralogical composition on ceramics different in structure and composition.