My out of date 2003 Standard Catalog of World Coins - 30th Edition - lists the 1910 25 pfennig G mintmark at $3 FINE, $8 VERY FINE, $18.50 EXTREMELY FINE, $35 UNCIRCULATED. Your coin is one of only 330,000 from the Karlsruhe Mint (the G mintmark). It is made of Nickel.
