Family ring (quest item)[]
There is a "desperate merchant" on the Dike after Chapter III has begun. Talk to him and he will ask you to retrieve a Family Ring. You can find the ring on a dead body in the swamp, directly behind the shrine of Melitele (to the northwest) on a little island. Return with the ring, and you get 100 
for your trouble.
Associated quest[]
Family ring (con artist)[]
This family ring which the Con artist gets Geralt to retrieve from the crypt in the sewers in Finders Keepers is also labelled "Family ring", but it's not a true quest item as it does not go into the quest items pocket.