Bulge Obverse And Concave Reverse Of British 1921 Half Crown > Counterfeit?

The general color and circulation wear look quite normal to me - I think it's a genuine coin. I've just examined the 1921 halfcrown in my own collection against a flat surface and the effect is similar!

The portrait of King George V on these halfcrowns was in very high relief, and a lot of metal was displaced when the coins were struck. This means the coins have a slightly concave reverse and convex obverse. The rim and lettering of all early George V silver and bronze coins are usually in much better condition on the obverse than on the reverse - I remember finding shillings and florins in change in the early 1970s with an obverse in almost Fine but the reverse almost worn flat. The Royal Mint partially solved the problem by modifying the effigy of George V in 1926, and then eliminated it by using a smaller head on the bronze coins and completely new reverse designs on the silver coins from 1927.

I agree with NumisRob, these coins had a sunken middle, on pennies of the era, its known as ghosting.

It was also issued when they had dropped back to 50% silver and used the first of three alloys which was 50% silver, 40% copper and 10% nickel as a whitener. It looked good when freshly made, but as they wore like your coins you got this blackened wear and the unnatural greyish white on the high points was that nickel whitener.

In 1922 they switched to 50/50 copper/silver and these coins were worse turned into brown/black lumps as they wore (The metals were alloyed, but biscuiting was common due to the metals being mixed while the copper was not hot enough (Annealling).

In 1927 they got the recipe right with 50% silver, 40% copper, 5% nickel and 5% zinc, the zinc made the coin less artificial looking as it wore.

Your coin is 100% real and is in high VG condition. 1921 is a common date so finding a nice one like this is not hard




This is a high VF coin and it shows clearly the wear is starting on the edges of the shield and on the edges of the King's head (The King was always struck in poor relief on this era coins). As you can see the nickel gave the coins an unnatural whitish colour when fresh.