Could it be a "black beauty", "Annealed Planchet", "Improperly Annealed", "Experimental Planchet", or just a plain washed coin? It weighs 5.56 grams and has a "green hue" tone to it. The rim has a slight sharp edge to it so much that if I scratch along the inner side, it will catch. And no it's not magnetic. Any thoughts please?

