Mineralogical transformations due to salt whitening agent in modern Hebron ceramics

•The study confirmed the role of halite in the bleaching of ceramics with high CaO content.•The characterization of the whitening effect highlights the important role of the salt in the process.•Significant differences in the microstructure of the calcareous clays with 5% added salt.•SEM-imagery shows the presence of rhombohedral voids which are due to the dissolution of the carbonates.