This 1 inch cube appears to be made of solid gold, yet is hard as diamond, and is unusually heavy even for gold, weighing in at 3 pounds. As an action you can speak the command word to activate it casting
Curse. When the cube is activated it attempts to absorb and destroy 500 gp worth of non-living material within a 60-foot radius of itself, starting with gold and gems and working down, consuming worn, carried, and magical items last (ignoring things that you are wearing but not carrying). If it finds enough material it works as expected. If it does not find enough value after absorbing everything it is able to it takes some of your life force to make up the difference. You take 8d6 Necrotic damage, and your max hitpoints decrease by 1d8 hit points for the remainder of the time you are attuned to this item. If you un-attune to this item it teleports to a random location.