Ring of Gax

This is a platinum ring set with an unusual stone, which cannot be identified even by a dwarf or jeweler. The stone has eight faces and can be turned so that any of the eight faces point forward. Each of these eight positions has a separate power, and can be used on command. However, the stone will frequently turn at random by itself, so it is necessary to try a random setting each time the ring is used. After that, the user must know how many faces the stone must be turned to the desired setting.