Guide:
Central Shadowfen, north of Hissmir Wayshrine, west of Hatching Pools Waysrhine.
Inside the “Gandranen Ruins” public dungeon. Start at Hissmir Wayshrine and head directly north. After you cross a river and a road you will come across the dungeon ruins. Stone doors leading into the dungeon are on the northern side. When you enter you will encounter a quest giver. The skyshard is in the hall behind her, to the left.