Hello Want, thanks for posting
One thing you could consider is a signet ring - my brother was given one that belonged to our grandfather and this is something that he wore all the time.
This is not really a gift that you make yourself but rings like this can be found for a good price so search around. They can be engraved with inititals or an emblem of choice.
I agree with loong and Ant, jewelry is very personal and it might be best to let your friend choose.