The Sun Chest is a limited edition Chance Chest that ran from June 13 to June 16th, 2014.
It is a 3x chest, and the new released Epic for the Chest is the Odin's Call, which is a Mono Earth.
1 Chest: 30 Gems
11 Chests: 300 Gems
40 Chests: 999 Gems
11 Chests: 5 Earth Fusion Boost Armor