Do mood rings contain mercury???

Question

Or any other dangerous chemical

Answer 1

I don't know about "Mercury", but there were some various types of "Mood Jewelry" being sold on the market a while back which were found to contain a certain about of "Lead".  Some of the "Mood Jewelry" had been manufactured in other countries outside of "The US" that do not have laws as strict as ours regarding what goes into toys and/or how they are made.  These were recalled.

Answer 2

No, they contain liquid crystals.  The crystals have different arrangements at different temperatures, and appear different colors depending on the temperature.  The same stuff is used for the thermometers you stick on the side of aquariums.  The chemical used is generally a cholesterol derivative.