You can equip each hero with up to four gems, one of each color. To do this, enter the Training Grounds and choose the Jewelry option, which is unlocked at Kingdom Level 13. See Training Grounds for interface help.
Each color affects a different stats. The colors are:
- Blue (Sapphire) for Ability Damage (Intelligence)
- Red (Ruby) for Strength
- Yellow (Citrine) for Life
- Green (Emerald) for Attack Speed (Agility)
They also increase your Battle Power, based only the level of the jewel.
Strategy Tip: Each level is worth 3x the previous one in BP, so if you find yourself with, say, Green Jewels of Lv 3, two of them in the inventory and two more on Heroes, you will fare better if you remove them from the heroes, forge a single, Lv 4 Gem, and equip it to a single hero. This also frees a slot in the other hero, that may be used for a lower level jewel.
See also "Strategy" section of Jewel Crafter
Embed in a Badge to grant wearer some extra Life
|600||1000||1665||2775||4625||7710 & +3.5%||12850 & +7%||21420 & +14%|
Embed in a Badge to grant wearer some extra Ability Damage
|150||250||420||700||1160||1940 & +3.5%||3230 & +7%||5380 & +14%|
Embed in a Badge to grant wearer some extra Strength (Min Strength / Max Strength)
|90/145||150/240||250/400||415/665||690/1105||1150/1845 & +3.5%||1920/3070 & +7%||3200/5120 & +14%|
Embed in a Badge to grant wearer some extra Attack Speed
|25||42||70||115||195||325 & +3.5%||540 & +7%||900 & +14%|
Level 1: Common
Level 2-3: Special
Level 4: Elite
Level 5-6: Wicked
Level 7+: Legendary