There are 5 types of orbs you can win in battles, all of them contain gold and hero cards. The bigger the orb, the more time it requires to unlock.
Common Orb unlocks in 3 hours and contains only common cards.
Rare Orb unlocks in 8 hours and contains common cards and also rare cards.
Royal Orb unlocks in 10 hours and contains both common and rare cards but in greater amounts.
Epic Orb unlocks in 12 hours and contains common, rare and even epic cards.
The last but not least, Ultimate Orb unlocks in 24 hours and contains a great amount of common, rare and epic cards.
Orbs from higher arenas contain more gold and cards.
The top 3 orbs can also be purchased in the shop. Purchased orbs open immediately.