Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks King's Tomb Star Stone / Blood Stone

I cannot enter the source temple because I apparently haven't collected enough Star Stones / Blood Stones (I tried using the unused blood stones in my inventory, same result). Icara said I need more. Zizzax is standing by Weaver and Icara - only normal dialogue available. I went back to the King's Tomb and there is a stone down inside giving off a pulsing purplish smokey light but I am not able to interact with it and I am unable to damage the sarcophagus. Can someone please help me figure out how to retrieve it? Thanks!