Toadstones - Something I Forgot to Mention About the Cheapside Hoard

These are Toadstones. They are the fossilized teeth of a fish from the Jurassic and Cretaceous periods. Instead of sharp teeth, they had a kind of pavement of teeth they used for grinding mollusk shells.  In the middle ages they were believed to come from the bumps on toads backs. Because toads were believed to be poisonous, the stones were believed to guard against poisons and disease - even the Plague, Leprosy, and Epilepsy.

There were a bunch of them found with the Cheapside Hoard.  They were frequently made into rings and other jewelry and worn as protection. Here's a pretty example.

The backs of these rings were open so the stone could be in contact with the skin of the wearer, to give them more potency.  Queen Elizabeth I was known to wear one and Shakespeare wrote about them in 'As You Like It'-  

Sweet are the uses of adversity;

Which, like the toad, ugly and venomous,
Wears yet a precious jewel in his head.