First let me say that I don't have any 1,000 oz. bars of silver (or gold for that matter!)- the biggest one (silver) I have is 100 oz. That said, I am curious about how people would go about authenticating 1,000 oz. bars of silver. It seems to me like one of those tools by Sigma Metalytics would not be appropriate for authenticating something this large. The reason is because I don't think it would be capable of seeing beyond just the surface of the bar. It could have copper on the inside.
Think about places like the COMEX that have lots of 1,000 bars. I remember hearing something years ago about how Nigeria (I think it was them) had a bunch of gold held in their central bank (Im thinking it was something like $200 million) that proved to be fake. With the quality of fakes coming from China having the potential to look very very good, I'd think this would (quietly perhaps) be an area of concern.
Any thoughts on this?