Does anybody know a nickname for Crystal. or just something to make it shorter.?

ok well i was thinking something like Chris but i was wanting it to be spelt really cool lol. what about kris? or kriss? idk so if anybody can think of anything then please tell me. thanx =) oh and i know it also sounds like a guys name but i like the name chris lol so...yeah it dont matter. if you have another good suggestion but it sounds like a guys name then go ahead and tell me. k thanx =)