Gems are used to improve the attributes of your champions. There are four different types of Gems: Ruby, Sapphire, Emerald, and Amethyst. In addition, each Gem has a level: Iron, Bronze, Silver, Gold, and Platinum. The higher the level, the more of a bonus the Gem gives.
For a full list of gems and what they do, click here.
To equip Gems, first tap "Power" on the main menu.
Select a Gem Page on the right side of the screen.
Then tap the Equip button at the bottom of the screen.
Now select a Gem from the menu on the right side. You can tap the "+" buttons to expand lists of the different types of Gems you have, and the "-" buttons to collapse the lists.
When you select a Gem, it is automatically placed in one of the slots for that type of Gem. There are three slots each for Rubies, Emeralds, and Sapphires, and one slot for Amethysts. You can tap a Gem again to remove it from its slot.
When you're done assigning Gems to slots, tap the Back icon in the upper right corner, and you will be prompted to save your Gem configuration.
You can create multiple Gem Pages with varying configurations of Gems to customize your champion's stats to your liking. Only one Gem Page can be assigned to a champion at a time, but a Gem can be assigned to more than one Gem Page. You start with two free Gem Pages; more Gem Pages can be purchased with Crystals. You can also rename your Gem Pages by tapping the pencil icon next to their names.
Assign Gem Pages to your champions by tapping a champion's portrait on the main menu, then selecting a Gem Page from the drop-down menu at the top of the screen.
You will also have the option of assigning a Gem Page to a champion before beginning a battle.
You can combine five Gems of the same level to create a new Gem of a higher level. Any five Gems of the same level can be combined; they don't have to all be Rubies, or all give bonuses to Armor, etc. The resulting Gem will always be one level higher than the Gems you combined (for example, five Bronze Gems combine to form one Silver Gem), but the type will always be random. It is not affected in any way by the types or stat bonuses of the combined Gems.
To combine Gems, first tap "Power" on the main menu to access the Gem menu. Then tap "Combine" in the menu on the left side of the screen.
Select five Gems from the list on the right side of the screen and tap them to place them into the combination slots. Remember, all five Gems must be the same level, but they can be any type. If you change your mind, you can tap the Gems again to remove them from the slots.
Once you've chosen the five Gems you want to combine, tap "Combine" in the middle of the screen.
The five Gems will be destroyed, and you will receive a shiny new Gem one level higher!
If you have a lot of Gems you want to combine, you can do so in a single tap rather than individually selecting every Gem. To do this, tap the "Combine All" button above and to the right of the main combination wheel.
This will take you to a new screen with three Combine buttons: one for creating Bronze Gems, one for creating Silver Gems, and one for creating Gold Gems.
Tapping the left button will automatically combine your Iron Gems to make as many Bronze Gems as possible. Tapping the middle button will combine your Bronze Gems to make Silver Gems, and tapping the right button will combine your Silver Gems to make Gold Gems.
Remember that using this function will always create the maximum possible number of Gems. In other words, if you have 11 Iron Gems, tapping the left button will always give you two Bronze Gems, with one Iron Gem left over; you cannot create Bronze Gems one at a time this way. You also cannot choose which Gems get combined, so if you have a Gem you want to keep, either assign it to a Gem Page or combine your Gems individually.
If you have a Gem that you're not using, you can reforge it to turn it into a different Gem of the same level. The resulting Gem will always be of a random type. Reforging a Gem costs Crystals; the cost depends on the level of the Gem you are reforging.
To reforge a Gem, first tap "Power" on the main menu to access the Gem menu. Then tap "Reforge" in the menu on the left side of the screen.
Select a Gem from the list on the right side of the screen and tap it to place it into the reforging slot. The price for reforging that Gem will be displayed at the bottom of the screen. If you change your mind, you can tap the Gem again to remove it from the slot.
Once you're ready to reforge your Gem, tap the "Reforge" button at the bottom of the screen.
Your Gem will be destroyed and replaced with a shiny new Gem of the same level!
If you'd like to have a little bit more control over what kind of Gem you get when reforging, you can choose to reforge a Gem several times at once. To do this, tap the "Reforge *9" button.
Your Gem will be reforged nine times. You will then be allowed to choose the result you want, or reforge again if you don't like any of the results.
That's not all there is to reforging, either! Reforging Gems will sometimes grant you a random selection of bonus Gems in addition to your newly-reforged one. The higher the level of the Gem you reforged, the more Gems you will receive.