Gem vault is an endless space for keeping valuable gems. It will help you to avoid the lack of free slots in your inventory. You can find the vault in the inventory screen.
Notice that sealed gems cannot be withdrawn from your vault, but their rating will remain. Only gems of 999 999 value and greater can be sealed into the vault. Each time you are sealing a gem to the vault, you will need to spend some magical ingredients, which are gained after rituals. The greater the value of a sealed gem is, the cheaper it takes to place it inside the vault.
Remember! If you seal a gem into the vault, you won't be able to take it back! It will stay inside forever.