Does anyone have the formula to figure the amount of pure silver
needed to raise the fineness of coin silver or lower to sterling
silver. I have some .625 fine Olympic coins that I want to raise to
.925. I know that 1 oz of .625 silver should have approximately 12.5
dwt ( 19.4375 grams ) of fine silver and 7.5 dwt ( 11.6625 grams ) of
alloy so to raise 1 oz of.625 to .925 I should need 4 ozs of pure
which would give me 92.5 dwt of silver and 7.5 dwt of alloy but there
must be an easy mathematical formula to use.