Magnesium’s softness makes it easy to polish to a very high degree but this softness is also its Achille’s heel. If the lapping machine is not precisely set or the technicians decide to take a brief peek at their social media feeds - poof - the cube is ruined. The trouble doesn’t end there, unfortunately. Unlike its better known alloy type, pure magnesium also happens to be a very delicate metal with simple moisture being its primary enemy. If the cubes are left in a humid environment the water vapor dulls those beautifully polished surfaces with an irreversible, milky type of tarnish. To prevent this from happening avoid touching them with sweaty fingers and leave them in their protective cubes for long term storage.