Great Britain minted all its silver coins in 92.5% (sterling) silver until 1920 when they debased silver coinage to 50% silver content. The missing silver was replaced with manganese causing these coins to tone darkly and in 1920 when several denominations were minted in both 92.5% and 50% silver this toning was the only way to tell the difference in silver content. In 1947 silver was removed completely from circulating coinage and at the same time the silver content of Maundy coins went back up to 0.925. Interestingly for a number of years Great Britain issued both 50% silver threepence coins and coins of the same denomination in nickel-brass (1937-1944). Bullion collectors should also be aware that in 1904 the silver threepence was minted at both 1.3g mass and the regular 1.41g mass.
We're happy to provide this free Great Britain silver coin value calculator. Just enter the numbers of each coin that you have and the total amount of silver and the silver value will be automatically displayed!