To upgrade your Bank, you need to collect the amount of each Gem type specified in your Bank. You can check your Gem requirements and total Gem progress by tapping on your Bank in the home screen. When you have enough Gems, tapping on your Bank will automatically upgrade it! This will subtract all the required Gems from your Gem total for each type. Now you should see your new Gem requirements for the next Bank upgrade!
The best part is: any extra Gems you collected before you upgraded are put towards the next upgrade. For example, if a Bank upgrade requires 100 Geography Gems, and you collect 200 before you upgrade, you will have 100 Geography Gems left to use towards the next upgrade!
There are 7 types of gems, each associated with subjects you will encounter in Jeopardy! World Tour: Arts and Literature, Entertainment, Geography, History, Language, Lifestyle and Science.
You will collect gems for each clue you answer correctly in the related subject. For example if you answer a History clue correctly, you will receive History gems.
Tip: Playing on your highest unlocked stage will earn you more gems for every correct response!
Gems are critical to collect because they lead to permanent bonuses!
Use gems to upgrade your Bank; when you upgrade, your Bank will permanently give you more Cash when you collect! You can upgrade your bank many times with gems for bigger boosts.
Upgrading your bank also gives you a permanent increase to your Gold Bar to Cash conversion: more Cash for less Gold Bars!