Hello! Looks like Berndorf Metalware Fabrik (BMF) mark before 1875 (two-head eagle instead of bear), but i'm not sure. And what does mean "AM"? http://s017.radikal.ru/i431/1504/93/7e3b2a4d0070.jpg Mark is on fork. If needed, I can add fork photo also. Is it big rare? Thank you, Nikolay