I have opened a dozen or two of these sealed containers you get for doing HE and some quests in the elemental evil campaign. If I look at them it says there is a chance of 1 of 4 items:
https://postimg.cc/image/q8ljzbdc1/However everytime I open one it only contains a worthless gemstone, usually a black pearl, which isn't listed as one of the options.
https://postimg.cc/image/pvu5tcsk1/Is this a bug?