I made one just to use as a place holder in a game I am currently working on, but I figured I could make a small set and post them here for anyone else who might have a use.

The animation is 6 frames, gray rock with a rune that glows blue/cyan. In the game I am working on it's just used for a puzzle where you would push them into a slot to open a door. Like so - http://imgur.com/yjQv4oc