Webster’s Revised Unabridged Dictionary · 1913
Toadstone
Toad′stone′ (·stōn′), 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.