It is covered with valuable jewels, okay, I am not completely sure what the true answer is From, once again, Merlin The sword Excalibur's scabbard did not make the wearer invisible or make it impossible to lose blood, it might in other versions but I am going off what I know, Also merlin and arthur who wore the scabbard, it did not shine as bright as the sun, to be honest all I know from the version I know exaclibur is a sword that can kill any living thing because it was forged in a dragons breath, it is the sword that the sorcerer merlin placed in the Stone for arthur to find. Phew! Man I love that show....