MArcomage

There are rares that destroy both players resources and her I see an uncommon with 0 cost potentially doing the same. Since you pick a card to use it, your deck will probably be build for it to do the same. I think it's to devastating for an uncommon.

Well, the downside to this card is that you will always lose all of your resources while your opponent can lose up to that maximum. So it's not as good as cards like Tornado which only cost 33 gems for getting rid of the enemy's resources. Maybe if it cost something (like 10 each) it would be better.

I wast talking about rares like Angel of destruction & New era.
Since it destoys up to your resources giving it a considerable cost might make it less rare-wordy. Also it would give the other player more time to react.

Angel of destruction does a considerable amount of damage and New era benefits you and your enemy by increasing the facilities. This card is just another variation of resource destruction.