The treasure chest can be gotten after you solve a riddle on a treasure map. Once you have one, you can click on it to create keys. The better the gem, the more different items you get. Once you have a key, you can use it to open the chest.
The first chest opened will drop an emblem, which can be charged for 250 Blood Crystals, giving your explorer a permanent +10 HP buff.
The chance of finding an orb in a chest is 1/36 per roll. You get 5 rolls for ruby keys, 7 for diamond keys. There is also a bonus roll available to donors.
Regular Chest Loot
Green Chest Loot
Green Chests can only be obtained after crafting the Spyglass.