I killed a ghost with a glass (legenday) axe with no enchanments on it, is it because its legendary or are ghosts in skyrim not limited to being hurt by only magic or silver,enchanted, or daedric weapons?

For those who are curious you can become a ghost on pc premanently by using the command 'addspell 0005030b'. This also works for npcs but they change back when a new area is loaded. No idea if there is a better place to post this if there is feel free to repost it.