Toadstone /(?)/

Toad·stone

Toadstone

n.
  1. 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. (Min.)
  2. Bufonite, formerly regarded as a precious stone, and worn as a jewel. See Bufonite.