The orbs are hollow balls of gold. The Sovereign's Orb is 6.5" in diameter. It weighs 42oz 7dwt. Queen Mary's orb is smaller: it measures 5.75" in diameter. It weighs 34oz 6dwt. Queen Mary's orb was originally set with hired jewels. Today it is set with imitations for display purposes. The Sovereign's Orb is currently set with over 600 precious stones and pearls.