The Liberty Chest is a 5x Chest that started on July 3rd, 2014 and ended on July 8th, 2014. The new Epic released in the chest is the Chaos Vanguard , which is a Mono Spirit Epic Armor.
This chest may be a reference to Independence Day for the U.S, which is on July 4th, 2014.
11 Chests: 450 Gems
40 Chests: 1,250 Gems
11 Chests: 5 Fire Fusion Boost Armors