Toadstones: The Medieval Gemstone Believed to Detect Poison
For centuries, Europeans believed that a mysterious gemstone grew inside the head of a toad. Set into gold rings, these so-called toadstones were credited with detecting poison, protecting their wearers and treating disease. Yet the stones were actually fossilised teeth from prehistoric fish. Explore their remarkable journey from Jurassic waters to medieval jewellery, Renaissance medicine and surviving museum collections.
