Toadstone

The Toadstone (not unlike the batrachite) is a mythical stone or gem supposed to be found in, or produced by, a toad. It is supposed to be an antidote to poison.

Additional recommended knowledge

Weighing the right way

What is the Correct Way to Check Repeatability in Balances?

Essential Laboratory Skills Guide

Allusions in literature

The toadstone is alluded to by Duke Senior in Shakespeare's As You Like It, in Act 2, Scene 1, lines 12 through 14:

"Sweet are the uses of adversity;
Which, like the toad, ugly and venomous,
Wears yet a precious jewel in his head".

Various other names

Some various other names of the toadstone are:

• Batrachite
• Brontia
• Ombria
• Garatronium
• Lapis Borax
• Lapis Bufonis
• Lapis Rubetæ
• Crapaut
• Crapaudine
• Krattenstein
• Crapontina

References

1. A collection of notes maintained by James Eason of the University of Chicago comprising excerpts from Thomas Nicols and other authors.
   
2. New Oxford American Dictionary, under the entry "toadstone".
   
3. The Complete Works of William Shakespeare by Crown Publishers Inc