HALLMARKS
GOLD
9C/Ct (England)
10K
12K or 12C/Ct
14K
14KP = plumb (exact) not used until circa 1976
375 = 9C
583 or 585 = 14K
750 = 18K
Eagle's head (France) = 18K
1/20 14K (or 12K) GF = gold filled
RGP = rolled gold plate
HGE = heavy gold electroplate
PLATINUM
900 Plat - 100 Irid (alloyed with 10% iridium)
Dog's head (France) after 1912
SILVER
925 = Sterling (92.5% silver) (United States)
Eagle Mark = Sterling (Mexico) between 1945 and circa 1970
Lion Passant Mark = Sterling (England)
Boar's head or Crab = 800 Silver (80% silver) (France)
Three Crowns Mark = 830 Silver (83% silver) (Sweden)
813H = 830 Silver (83%) (Finland)
916H = 935 Silver (93.5% silver) (Finland)
Dog's head on plaque = 750 (75% silver) Austria (1866-1937)
Lion's head on plaque = 750 Silver (75% silver) Austria (1866-1937)
800, 825, 830, 850 = European or Continental Silver marks
900 = American (or coin silver) before 1906
EPNS = electroplated nickel silver
German Silver = NO silver content (copper, nickel, zinc alloy)
Nickel Silver = NO silver content (copper, nickel, zinc alloy)
Alpaca = 2% silver with copper, nickel, zinc
British Hallmarks: Complex system. You will need to get yourself a book to decipher the fineness of the metal, the date the piece was made and the location it was made.