Interesting 40% Silver Kennedy Half Find

Hi,

1965 to 1970 , 40% Kennedys should weigh 11.5 grams. a 90% silver half should weigh 12.5 grams. I see why you have a question on it. The likely scenario and one that wouldn't be too uncommon is that the planchet was rolled a fraction thick.

These halves are clad and are made of outer layers that are an alloy of .800 silver and .200 copper. That is bonded to an inner core of an alloy of .209 silver and .719 copper.

I suspect that the coin you referenced is probably a 1965 dated piece with one of the outer layers missing. It would account for the much lower weight and they can be cute by saying the overall silver content is 25% as opposed to the 40%.

Therefore, it is not a matter of the silver in the coin actually being different alloys of a lower percentage. It is a matter of figuring out the approximate silver content in the 1965 coin after it was determined that an outer layer is missing.

Thanks,
Bill

I suspect that NGC just pulled something out of their hats. I remember seeing another slabbed 1965 half in an article by Mike Diamond that was slabbed as being struck on 90% silver dime stock. NGC proposed that dime stock got punched into a half dollar sized (blank) planchet resulting in a very low weight coin.

If I remember right, Mike analyzed the coin every which way possible and proved that at least it was not on 90% dime stock as stated on the NGC slab.

Further, I think he sent the coin to Chris Pilliod (in PA, I think), who is a metals expert. More tests were done and he also concluded that it was not as labeled on the slab but may have been struck on a planchet with a clad layer missing.

Again, if memory serves Mikes conclusions were conclusive as to what the coin is not, but exactly what it was remained a bit elusive. Some of the tests to determine the exact nature of the metal involved created numbers that fit a few possibilities but did not pinpoint the alloy of the metal used to strike the coin.

The point here is that a coin of a similar nature was slabbed incorrectly by NGC as they seemed not to do the type of exhaustive study needed to verify what the coin was made of as was done by Mike and Chris. If I had to choose results found by Mike D. working with Chris P. vs. something on a slab, I'd go with Mike and Chris every time.

So your coin is probably normal. In this post I was trying to account for the NGC slab that you mentioned.

Thanks,
Bill