Much has been written about toadstones. They are mentioned in literature as far back as the Roman writer Pliny the Elder, who died in the famous AD 79 eruption of Mount Vesuvius, which destroyed Pompeii. In fact, it has been suggested that the legends about toadstones originated with the name 'Batrachites' (frogstone) given to them by Pliny (Lankester 1920).
Lankester stated that they were so-named because the drab colour resembled that of a toad. Subsequently the vivid imaginations of medieval physicians may have been responsible for myths about the origin and mystical powers of toadstones.
The naturalist Robert Brookes (1763, p. 162) described the colour and shape of toadstones, even remarking that: '...and some suppose it to be the tooth of a fish; but this does not seem to agree with its shape'.
Toadstones were alluded to in William Shakespeare's play As You Like It .
In Act 2, Scene 1, Duke Senior says:
'Sweet the uses of adversity.
Which, like the toad, ugly and venomous,
Wears yet a precious jewel in his head'