jats:pThis article examines the properties of powerful stones in medieval Iceland, focusing on the applications of such stones in learned treatises and in saga literature. The relationships between humans and stones in these sources offer a useful case study for engaging with medieval Icelandic conceptions of the interplay between the human and the non-human world, specifically in terms of bodily health and enhancement. The article has two parts: the first part examines the Old Norse-Icelandic lapidary tradition as witnessed in the translated lapidary text in AM 194 8vo (ff. 45v–48v), providing an overview of the range of physiological, emotional and cognitive effects stones were thought to have on humans (from the curative and prophylactic to the enhancive); the second part discusses the appearance of stones in thirteenth- and fourteenth-century saga literature, examining how their properties alter and develop over time and across genres. This research builds on the growing bodies of scholarship on dis/ability and medicine in Old Norse-Icelandic literature and finds that the presentation of powerful stones in these texts suggests an understanding of the human body and mind as fundamentally “open” to the vibrant, material world. It therefore further supplements contemporary research into conceptions of the self in medieval Iceland, as well as attitudes towards the non-human world.</jats:p>