What is "toadstone"

Toadstone \Toad"stone`\, n.

1. (Min.) A local name for the igneous rocks of Derbyshire, England; -- said by some to be derived from the German todter stein, meaning dead stone, that is, stone which contains no ores.

2. Bufonite, formerly regarded as a precious stone, and worn as a jewel. See Bufonite.

"stone or stone-like object, supposedly magical (with healing or protective power) and found in the heads of certain toads," 1550s, from toad + stone (n.). Translating Greek batrakhites, Medieval Latin bufonites; compare also French crapaudine (13c.), German krötenstein.\n\nThe Crapadine or Toadstone, we speak of before, you shall prove to be a true one, if the Toad lift himself so up against it, when it is shew'd or held to him, as if he would come at it, and leap to catch it away: he doth so much envy that Man should have that stone.

["Eighteen Books of the Secrets of Art & Nature," 1661]

n. A small stone, once believed to be a jewel embedded in the head of a toad, worn as an amulet.

The toadstone, also known as bufonite, is a mythical stone or gem that was thought to be found in the head of a toad. It was supposed to be an antidote to poison and in this it is not unlike Batrachite, supposedly formed in the heads of frogs. Toadstones were actually the button-like fossilized teeth of Lepidotes, an extinct genus of ray-finned fish from the Jurassic and Cretaceous periods. They appeared to be "stones that are perfect in form" and were set by European jewellers into magical rings and amulets from Medieval times until the 18th century.