ok. disclaimer first. I tried to search for it, and found nothing but associated sound file on wowhead and no comments, so I apologize if these were discussed before, but I'm intrigued and need to vent somewhere
anyway, these things are currently lying in game files and nobody seems to care
there are few of them and its basically same thing just colored to different gem colors currently in use by jewelcrafters.
I don't know about anyone else, but when I read EARTHEN + JEWEL, I immediately think of Deepholm of all things. I realise I'm grasping at straws here, but what if next stage of saving Azeroth requires us to go underground? After all, that sword went in pretty deep. I'm not implying it will be some major piece of content, perhaps some WQs? No?
At the very least, I think its safe to assume that we're looking at future jewelcrafting profession updates.