This paper explores the possible relationships between Bronze Age petroglyphs and the rock medium on which they are carved, focusing on the rock art area in Boglösa, Uppland. With a new materialist perspective, the study investigates how the rock, with its natural features, influenced the placement and potential meanings of petroglyphs, acting as an active agent in the rock art tradition. The result of the study shows probable interactions between the petroglyphs and the rock that cannot easily be dismissed as random, and highlights how consideration for the physical properties of rock may be beneficial for the study and interpretation of Bronze Age rock art.