The health conscious will know that potassium is good for the heart and you can get plenty by eating bananas. Not too many people know, or care, that potassium is a silvery metal. A good reason for this is that it only stays a metal in the vacuum of space or when surrounded by a noble gas. The slightest trace of oxygen - or most any other element for that matter - quickly reacts with it to form compounds. Even under mineral oil, which is very inert, a piece of potassium will manage to tarnish from trace impurities.

Potassium in elemental form is quite difficult to find generally speaking but is an even bigger challenge to get it in ampule form where that delicate mirror finish can be appreciated. This cube guarantees it will stay free of oxides permanently.