Levi's stone was the carbuncle, that beams like lightning, as, likewise, the faces of that tribe beamed with piety and erudition. This stone has the virtue of making him who wears it wise; but true wisdom is the fear of God, and it was this tribe alone that did not join in the worship of the Golden Calf.
Judah's stone was the green emerald, that has the power of making its owner victorious in battle, a fitting stone for this tribe from which springs the Jewish dynasty of kings, that routed its enemies. The color green alludes to the shame that turned Judah's countenance green when he publicly confessed his crime with Tamar.