Compare the reverse detail of the two pennies. An astute eye detects a difference. Both are just slightly worn and condition is Extremely Fine, an elusive grade for a 1928-D penny. A collector seeking top quality notices one reverse displays weakness of the lettering along the rim an indistinct rim and faded lines in the wheat stalk. The reverse design of the 1921 penny, shown below, features Britannia holding a trident in her left hand and resting her right hand on a shield bearing the combined crosses of the Union Flag.

The 1921 penny is a classic example of a circulating George V coin with an instantly recognisable design.dot specimen set : https://www.coinsandcanada.com/coins-articles.php?article=the-unique-canadian-1936-dot-specimen-set&id=540 TIP: Whatever you do, don’t clean your coins, no matter how dirty they look! Cleaning a coin will not increase its value. Instead… it will actually slash its value by 50% or more.

Values of Coins of the UK - The Penny (Copper or Bronze) Values of Coins of England and Great Britain ('Coins of the UK') by Tony ClaytonEye appeal because of crisp detail places one ahead of the other in desirability to collectors. A search for quality among Denver pennies adds to the challenge of finding the right coin. Consider all with well-defined details solid for the grade and value. As premiums rise subtleties gain importance. As the 1921 penny was issued for circulation it is only natural that some are in better condition than others, which is why the value can vary so much. Design Of The 1921 Penny