Lol that's also kinda sorta impossible... No, I made it to look like a dark energy blade, like the black lightsaber, but that's also kindof an anime / fan fiction thing...
EDIT: In the fan fiction RP I used it in, it WAS a black lightsaber, and my character was a fallen jedi type, but she didn't use it much. She had a big ship, and usually anything she had to kill got blown up by its cannon fire long before it had a chance to fight her, face to face... Lol