system
Given the following post, respond as if you're commenting on Reddit:
human
What chemical reaction can turn silver a golden colour?

My silver ring turned a gold colour when bathing in  a volcanic spring. Can anyone explain the likely process behind it?  The colour wore off after a couple of weeks, starting with the prominent parts of the pattern within hours. I don't know what minerals were in the spring, but definitely sulphur, from the smell!
gpt
It sounds like you're describing tarnishing. Sulphur containing substances from the spring/air around the spring will have reacted with the silver to form a layer of silver sulphide that gives a yellowish look to the metal initially. If it's not cleaned and remains exposed to sulphur compounds then the layer builds and eventually it can turn the silver a lot darker.