Exodus 28:29

onyx stones, and setting stones for the ephod and for the breastpiece.

“These are the garments which they shall make: a breastpiece and an ephod and a robe and a tunic of checkered work, a turban and a sash, and they shall make holy garments for Aaron your brother and his sons, in order for him to minister as priest to Me.

“You shall put the two stones on the shoulder pieces of the ephod, as stones of remembrance for the sons of Israel, and Aaron shall bear their names before Yahweh on his two shoulders for remembrance.

Then Gideon made it into an ephod and placed it in his city, Ophrah, and all Israel played the harlot with it there, so that it became a snare to Gideon and his household.