Saw these at the coin shop recently. They are 62.5% silver 5 Mark coins from 1951. It's kind of a weird art deco style design. They were different, so I grabbed them.
The really neat thing about these us that they're stamped on the edge. It says "Einigkeit und Recht und Freiheit", which translates to "Unity and Justice and Freedom". Apparently this is (or maybe was?) the national motto of Germany.
I really like these a lot.