That's a very nice piece, Noah. One of my specialties is German coins of the Second Reich. It looks like the Long Beard variety, which in 2006 was worth $250 in Fine condition. The "D" means that the coin was struck at the Munich Mint (which still strikes coins today).

For the sake of you Suitors who are not coin collectors: after 1873, all Germans used the same coins from 1 Pfennig up through 1 Mark. For 2 Mark, 3 Mark and 5 Mark coins (silver) and 5 Mark (briefly), 10 Mark and 20 Mark (gold), most coins bore the portrait of the Kaiser and King of Prussia; but the other German kingdoms, principalities. grand duchies, duchies, free cities and so on were allowed to mint their own coinage, using the common reverse and the imperial coinage standards. The Duchy of Saxe-Meiningen was located in what is now the "Land" (State) of Thuringia; and the last Duke abdicated in 1918. Noah has, not just a valuable and attractive coin, but a nice piece of history -- which is one reason why I, too, collect German coins.