Gems are IAP currency used in the game, similar to gold and hearts. You can check the balance under your character's name at the top of the screen. 

Ways to Acquire Gems:

- Purchase Gems as an in-app purchse with real-world money.

- Earn Gems through various in-game events and achievements.

- Receive Gems as level-up rewards.

Ways to Use Gems:

- Purchase items within the in-game store.

- Buy items in the Robin Shop.

- Use Gems for quests, upgrading worktables, crafting tools, and unlocking new areas.

- Exchange Gems for Gold or Hearts.

- Change the appearance of your character or username.