In a world that is always shifting between the middle ages and the age of discovery, mages learned to create powerful artifacts.
They call them Heirloom Gems as they are meant to be given from one generation to the next.
Worn they learn skills and knowledge alongside their hosts.
What they learned they later give to the next bearer.
However, they never stop learning.
Slowly mankind finds out that they underestimated the Heirloom Gems.
Older gems start to learn and pass on traits and behavior that their owners shared.
Maybe even more.