toadstones

   A widespread medieval opinion was that a toad has a jewel embedded in its head, which could detect and counteract poisons, heal bites and stings, and help women in childbirth. Various semi-precious stones, and also the teeth of certain fossil fish, were called toadstones and worn as pendants or rings. The traditional way to get one was to bury a toad in a pot in an anthill for the ants to eat, till only the bones and the stone were left. An anonymous treatise of the 1660s explains:

   It must bee a Toade that is very greate and old and hath Lived Long in hedges or diches or a fenne of Reeds because it will be many years or ever the stone can come to any bignesse [It] is off Cullar eyther white or a Littel darkish Browne or Blacke haveing in the middest of the stone Like unto an Eye beeing of a greenish Cullar. Especially if the stone bee taken from the Toade alive and so is off most vertue off operation Butt myself had one wch was black and spotted with redd spotts wch I did set in a ring off gold off 20/- vallew and I sold it ffor Ј6. Butt I never since could meete with such another. (BM Sloane 2539, fo. 34; cited in Evans, 1922: 150)