The loot for Morpheus's Treasure Chest is somewhat complicated to explain, but I'll try. You will always get 3 pieces of loot and some gold. From my experience, and my guilds experience, you will ALWAYS get a piece of Morpheus leather gear from the chest. After that, you will get a random "unsealed" level 50 weapon or armor piece. I say unsealed because it's the unsealed version of sealed gear from high level mobs. The last piece of loot you will get is somewhat random. My personal experience has lead it to be two starlight archeum crystals and two wild ginseng seeds. This all the knowledge I could gather on the chest from my own experience and the experience of my guild.

Edit: 4th time opening I got a ruby as the "random" loot.