Tasting the silvery substance feels... odd. It's metallic, and your tongue goes somewhat numb and tingly. Climent says "I'd guess that it's quicksilver Master Dwarf... Wouldn't suggest eating much more of it. It can drive you mad."
He pauses for a moment. Standing closer now it would appear that the boxes are not actually attached to anything, they are just sitting on the floor.
"No, not the first empire. That would be the Ancients, and no one alive, leastwise no one I have ever heard of, has ever seen one of their artifacts... I suspect that this was crafted by the Eld however, which still makes it in the neighborhood of a thousand years old... Far older than this room, which I would guess to be Thulian.
These boxes may indeed be worth considerable coin, though, as Gargrim astutely mentioned I would be leery of what their purpose might be. The Eld were creatures of chaos to the highest degree. From what I have read, they make the mercurial nature of the Elves seem like the bedrock stability of the Dwarves by comparison.