This Photo shows the "D", and the "O" in the word Dollar on the coin. The entire phrase "HALF DOLLAR", appears to me to have been double struck. Or is this one of those "Machine errors"?
The correct term would be "doubled die", not double struck. A doubled die occurs when a working die is produced from a working hub. A second strike is required to complete the working die, but not always are the hub and the die aligned correctly. Unfortunately, your coin is the result of machine doubling which happens when the hammer die loosens and vibrates rapidly back and forth which scrapes part of the design away.
Suggestion.. Create your future error or variety questions over at the Error Coins forum of CoinTalk. First and most important is to find out and to learn what you have.. Worry about premiums last. Hey but good news. Your 90% Silver Kennedy has a melt value of about $9.31 MD Mechanical (Machine) doubling considered worthless doubling adds no extra value.
