A couple of years ago, I bought a hammered threepence from a coinshow from the reign of Queen Elizabeth I. I am wondering if the coin is authentic or a forgery.
The piece has many problems, but it looks authentic. The planchet is either cracked, or more likely cut (the long, straight mark). It has also been "clipped" - the edges were trimmed a bit by unscrupulous folk to steal some of the silver, which they resold for profit.
Yes - looks spot on to me. Elizabeth I Silver hammered coins are actually quite common in the UK - probably the most common hammered coin to turn up. In that damaged condition would be found at any of our coin fairs and exhibitions for a few tens of pounds, depending on the view the dealer took. I believe yours is a Fourth issue Threepence S2566, date appears to be 1569. The mint mark (at the very top on both sides) is obscured - it looks like the Ermine, but that is for 1572-3 - it could be the central part of the Coronet is all that is left, and that fits with 1567-1570. (It is not uncommon for mint marks to be found out of date as dies were constantly being re-used.) The damage looks to me to have been caused by the coin being bent and cracked before being re-straightened, but it could also have been a crack in the silver blank used. I hope that helps.
No doubt it looks authentic and the color is spot on in my opinion. The condition leaves a little to be desired, but a cool coin none the less.
A couple of comments. To me this does not look clipped but more likely hammered off-center. Counterfeits of this type as described in my new book - Forgotten Coins at Amazon Books in the World Counterfeit 1500-1800 chapter these basically come in two major CCC alloys: High tin/antimony and debased silver. The debased silver alloy however may occur with some monarchs like Henry VIII during periods of low silver inventory so to make a long story short compare the weight to the weight listed in KM. If lower than regal its proabably high tin. Antimony was added for one major purpose to add strength to the alloy and sometimes we do see lead to bring its overall weight up to regal - but almost always its never reached to the value listed in KM. John Lorenzo, Numismatist, United States