finding gems for the rings

you know that to activate your useless rings you must seek out spirit core gems and their activation block in order to power them up. but what are these gems realy? who made them and why where you given these rings and this quest... well you forgot to ask but there seems to be loot and cool shit so that is reason enough to plug these bad bois in!
they seem to be located at ancent holy sights and ruins of a past civilization. maps can reveal the truth.