Okay,so I just found a pet of mine with a dark mage amulet in the TC,and I see the Mage has quests.What does the Mage give you for bringing back the amulet?

Most importantly,should I sell the thing or do the quest?

its risky to turn them in for tomes. The shards aren't worth much so if you need the sp then just sell the amulet. If you have plenty to spare then you can take the risk. You can earn an achievement if you give an amulet to the mage.