Being a European collector I can say these are pretty common, even the older ones. I'm guessing it's a 10 pfennig coin which was minted 1949-2001. These were minted in masses as there were no 20 pfennig coins. The legend was changed in 1950 from "BANK DEUTSCHER LÄNDER" to "BUNDESREPUBLIK DEUTSCHLAND". They are made of brass plated steel.

Edited by X2an
04/12/2015 06:49 am