Examples from the Web for toadstone
The toadstone was supposed to be specially powerful against witchcraft and poison.
The setting is of silver, and the jewel which it carries is called a toadstone.Ten Thousand Wonderful Things|Edmund Fillingham King
Popular names for them are "whinstone," "greenstone," "toadstone" and "trap."
Last of all he showed me a toadstone amulet set in silver, a charm to prevent and ward off the spells of fairies.The Heather-Moon|C. N. Williamson and A. M. Williamson
Dark and weird are the legends relating to the power of the toadstone, that amulet so highly prized by witches and astrologers.