The WoW Crystal-encased chest is one of several treasures in Zaralek Cavern, the new zone introduced with the World of Warcraft 10.1 update. Just like the Dreamer's Bounty and the Old Trunk, you'll need to find and interact with certain objects to get inside and claim the rewards.
As well as the new zone, the Embers of Neltharian patch offers new dragon glyphs, an additional dragonriding mount, and various other quests and activities to get stuck into. Aberrus, the Shadowed Crucible raid also arrives with the start of season two, so there's no shortage of things to do around the Dragon Isles. If you've got your heart set on collecting treasure, here's how to open the WoW Crystal-encased chest.
How to open the WoW Crystal-encased chest
The Crystal-encased chest is found at the edge of Zaralek Cavern, northwest of Glimmerogg. When you first arrive there, it won't look very chest-like—it's encased in crystal after all—so you need to figure out how to break it open to get to the chest.
As it turns out, you need to beat crystal with crystal, so head north to the location marked on the map above (coordinates 37,68) and look for a blue crystal floating above a ledge. Interact with it, and it will start floating up. Now head a little way to the south and look for a yellow crystal. Again, you can check the exact location above; the coordinates for this one are 39,73. Interact with it, then return to the location of the chest.
You should see that the two crystals have taken up positions on either side of the "chest", and as you approach, they'll start shooting blue beams into it, revealing the chest beneath. Loot the chest to receive an intellect trinket and more Whelpling's Shadowflame Crest Fragments.