The Dragonhide Chest is a limited edition Chance Chest that was released on July 16th, 2015 and ended on July 23rd, 2015. The new Dragonforged released in the chest is the Dignified Dragonhide, which is an Earth/Fire Dragonforged Armor.
There is a 2x chance of receiving a Dragonforged+
1 Chest: 25 Gems
11 Chests: 250 Gems
24 Chests: 500 Gems
52 Chests: 1000 Gems