2.33 g 18.034 mm 50% silver, 50% copper (30.6M) 80% silver, 20% copper (32.3M) Wiki list the canada dime as the above numbers what does 30.6M and 32.3M stand for? John
If I'm not mistaken, '67 was the transition year - all '66 were 80%, all '68 were 50%, '67 was a pot shot.
Both 1967 and 1968 were transition years. With the rising cost of silver, the fineness was reduced from .8 to .5 in 1967. The cost of silver continued upward, so the mint dropped the .5 in favor of pure nickel some time in 1968.