Four basalt stones of hopper-rubber (Olynthus) mills were sampled for chemical analysis; two were found at Nahal Tut and two, from ‘En Hofez. All were dated on the basis of stratigraphy to the second half of the fourth century BCE. The chemical examination established that the millstones from Nahal Tut were manufactured in the area of Nisyros, in the Aegean region.