Shard is inside Tomb of the Apostates solo dungeon. Dungeon’s entrance is covered in vines and you best approach it from north. “Ancient Scrolls of the Dwemer I-B” lorebook is near the entrance. As you enter the dungeon, turn left and go toward the area with lots of water. It is located inside this space.
Tomb of the Apostates entrance.
Tomb of the Apostates map location.
Several groups of risen found in the same area.
Exact location of the shard.