Copper, nature's only red metal! A kitchen full of polished copper pots and pans is a sight to behold and so are these cubes that you can't resist picking up and playing with. But, unlike the case with your pots, cleaning these delicate cubes is inadvisable. If you're clumsy enough to get ketchup on it use a cotton ball, water and a little prayer.

So yeah, it bears repeating: copper is delicate. Avoid touching it with your bare hands. The oils and acids will stain it permanently. Even leaving it out in open air will eventually.... have you seen the Statue of Liberty?

10mm cube weight is 8.9±0.5g.

25.4mm cube weight is 146±3g.