Guide:
Southern Greenshade, southeast of Greenheart Wayshrine.
Found inside Carac Dena solo dungeon. This is an Ogre cave. They usually stand alone. Groups of two or more are rare. Collectible is, as in many other dungeons, inside the last cave room. Specifically, it is in the northwestern corner of the last room. This is a rather large room. If you are not looking for the shard you can easily skip it. The last room is guarded by Urumaz the Terrifying. This mob grants “Completed: Carac Dena” achievement upon death.