urim and thummim

                             

Stones used by the Jewish high priest to seek divination as directed by Moses. They would tell divine will by  rendering "go" or " no go" to questions asked of the priest. They were not used by Moses but by Aaron, Joshua, and successors.

Some translate the words urim and thummin to mean “curse” and “blessing,” others simply “dark” and “light,” although the literal translation seems to be “light” and “perfections.” There is no proof that there were only two items; some early rabbis believed that the urim and thummin were a series of stones.

jpr: It seems the stones would be tossed until only one stone landed with its inscription face up.