The paper presents new observations on the use and avoidance of different red scoria rocks on Easter Island (Rapa Nui), made during fieldwork. It describes the different facies of the rock, their origins, their nature and their context of quarrying and use. From the latter, it is inferred that, for the prehistoric Rapanui, the meaning of red scoria transcended practical utility. A combination of stone context and ethnographic analogy suggests what this meaning or these meanings might be. Stone use on the Island is presented as a model against which the stone use of other prehistoric cultures might be measured.