Exodus 39:2
"And he made the ephod of gold, blue, and purple, and scarlet, and fine twined linen."
Cross References (ranked by relevance)
Leviticus 8:7
And he put upon him the coat, and girded him with the girdle, and clothed him with the robe, and put the ephod upon him, and he girded him with the curious girdle of the ephod, and bound it unto him therewith.
Exodus 25:7
Onyx stones, and stones to be set in the ephod, and in the breastplate.