Have them use gold, and blue, purple and scarlet yarn, and fine linen.1
References for Exodus 28:5
"Make the ephod2 of gold, and of blue, purple and scarlet yarn, and of finely twisted linen--the work of a skilled craftsman.
References for Exodus 28:6
It is to have two shoulder pieces attached to two of its corners, so it can be fastened.
Its skillfully woven waistband3 is to be like it--of one piece with the ephod and made with gold, and with blue, purple and scarlet yarn, and with finely twisted linen.
References for Exodus 28:8