Confederation (1967) Silver Quarters Percentage Determination

Hello, 

I have two confederation quarters with me that I have tested for weight. Both show up as 6 grams on the scale. There is a note on both 80% and 50% that weight may be the same (5.83 grams) and the mint states that the 50% quarter weighs 5.05 grams. As my scale does not have decimal places, it must be a rounded number. Their dimensions are also stated to be the same at around 1.78 mm thick and 23.88 wide. With this, as silver is a much heavier metal than copper, it would make sense that the weight of the coin that is 50% is lower. This is also the case with 80 vs 50% dimes. So, if each weighs 6 grams, would that be an effective way to guess if it is 80 or 50%? I am asking as I want to make a counter proposal to my LCS. 

I have been asked to put the quarters Numista pages here: 

N#312432

N#367 
 

Thanks! 

Please, show us the numista link to your coin and the images of both sides of your coin.

Has anyone ever tried to distinguish the two types with the use of a neodymium magnete?

If I understand the video below correctly, the degree of attraction to such a magnete is dependent on the silver content.

https://www.youtube.com/watch?v=vOVZv-60Uu4

ArnoV

Has anyone ever tried to distinguish the two types with the use of a neodymium magnet?

 

If I understand the video below correctly, the degree of attraction to such a magnet is dependent on the silver content.

https://www.youtube.com/watch?v=vOVZv-60Uu4

Ok so I tried that on both my quarters and compared them to coins whose metal content I was sure of and were similar (An 80% quarter - N#371, 1942, a 92.5% Newfoundland quarter - N#2785, 1917). The magnet slid off both quarters notably faster than it did on the higher purity quarters.  I then compared the rate to two larger coins of both purities (80% Canadian half dollar of the same year N#306, and 1920 British Half Crown 0f 50% - N#21964) and their rates reflected that of the 80% quarter compared to the 1967s in my possession. If that is the case, how does they have the same dimensions as the 80% quarters? 

ArnoV

Has anyone ever tried to distinguish the two types with the use of a neodymium magnete?

 

A magnet slide easily distinguishes coins with different silver content.  I took 3 coins of similar diameter and weight with silver content of .500, .640 and .800 and “raced” them against each other.  The speed down the slide was inverse of the silver content.  Here are 3 movies showing this:

https://www.dropbox.com/s/0kess0kgvjfg69l/800v640.MOV?dl=0 

https://www.dropbox.com/s/xzrdrwei22gdwtj/800v500a.MOV?dl=0 

https://www.dropbox.com/s/e7mi9vsryhpes59/500v640.MOV?dl=0

and stills from each: