What are the game currencies?

Soft Currency (Silver Coins)

These silver coins are obtained from chests, donating cards and gold packs (Hard currency purchase). Silver coins are used to upgrade cards and purchase other cards.

Hard Currency (Gold Coins)

These coins are obtained in small quantity from achievements and Victory chests and in much bigger quantities from purchasing them in the store menu. Gold coins are used to skip chest timers and purchase gold packs and chests