Exodus 4:9

4:9 And if they do not believe even these two signs or listen to you, then take some water from the Nile and pour it out on the dry ground. The water you take out of the Nile will become blood on the dry ground.”

Exodus 28:21

28:21 The stones are to be for the names of the sons of Israel, twelve, according to the number of their names. Each name according to the twelve tribes is to be like the engravings of a seal.