Finally hunted down this really tough coin. I strongly believe that it's genuine and it's definitely different to any other coins that I have. Rings differently and is just wierd! Sounds and feels like lead but just has this odd greyish color which I have never seen before. More information can be found here: http://www.charm.ru/library/antimony.htm and here: http://www.zeno.ru/showphoto.php?photo=26538
That's pretty cool. According to wikipedia antimony is toxic. That would explain the lack of coinage.http://en.wikipedia.org/wiki/Antimony
Frank Robinson wrote in his book about buying one of these. You could always ask his opinion also if you wanted. He is an expert in Chinese coins, in fact he is selling his best stuff in Hong Kong auction soon. Edit: Not that you are not an expert in Chinese gxseries, I was just suggesting since Frank owned some of these in the past, so has hands on experience with them, something most others do not. They are very rare coins. Congratulations on the find.
I fell in love with chemistry as a child even harder than I fell in love with coin collecting. This is very, very cool. People ask occasionally about making their own coins. I'd love to press (as opposed to "strike") a coin or two from sodium or potassium. You'd get some amazing natural toning, but you'd need a high-speed video camera to capture it...
I knew there was something tickling at my memory about this, and I finally found it: Antimony Coin It's certainly not a "coin" in the same sense as the OP's outstanding find, regardless of what the producer calls it. But I'm still thinking about starting to assemble a collection of these. (I note that the same guy also plans to offer a "mercury coin", but it's just a blob of the stuff in a tube. He really should mint them in a cryo-freezer and ship them on dry ice. )
Lots of metals are toxic (Lead, Mercury, Cadmium just to name a few) but it depends on how long you are exposed to it and the concentration.
