Batrachite

Batrachites were gemstones, supposedly found in frogs, to which ancient physicians and naturalists attributed the virtue of resisting poison. They resembled frogs in color.

Toadstone is a similar mythical stone, supposed to be found in toads.

The term batrachite is also used for a batrachian (or frog) fossil.

References

1.  This article incorporates text from a publication now in the public domain: Chambers, Ephraim, ed. (1728). "^{article name needed}". Cyclopædia, or an Universal Dictionary of Arts and Sciences (first ed.). James and John Knapton, et al. 

1. "Batrachite". Oxford English Dictionary. URL accessed 2006-03-05.