I've always been a bit flummoxed by these - why were some 1967 Canadian coins minted in 80% silver and others in 50%? They both seem to have been minted in large numbers intended for circulation. Where higher purities released to meet regional demand (just as silver dollars were minted for use in the American West long after they had fallen out of favor in the east)? Did silver prices spike in mid year, causing a debasement in mid-production? Or was it something entirely different? Also, is there any easy way to distinguish the two? Both seem to have been minted just to drive collectors crazy and force the 80% (junk bullion) issues to trade at 50% silver prices! And they're listed in Krause as having the same weight.
Hmm. That sounds reasonable. How would one conduct a specific gravity test? I've heard of them, but am a bit weak on the theory / practice.
I wonder - would a tissue test work for telling 50% and 80% silver coinage apart? I'm going to have to get a handful of 'unknown' Canadian centennial coins and try it out.
