This ancient stone slate seems to be covered completely in various glowing runes. It has a sheet of some kind of glass across the front. the runes around which seem to be of different make then the rest. It has been made to keep track of various things for you. It shows a map of the area, keeps track of your inventory, has a telescoping view and keeps track of your current tasks.
it also has a handy belt clip. Who knows what else it can do.