a corberyl

This clear, faceted gem plays wondrous tricks with the light it receives: depending on external conditions, its colour changes from bluish-green to orange to purple-red. It seems as if the gem were a living creature itself, waking up and sleeping as time passes.

It is a corberyl.
It weighs a couple of ounces.

You identify a corberyl.
It weighs two ounces, and it is worth about 105 lauren.
Its keywords are corberyl, jewel, and gem.