In the middle of 1982, the U.S. Mint changed the planchets (the blank disk from which the coin is made) from striking copper-alloy to copper-plated zinc for cost reasons. However, it was difficult ...

But a few bronze planchets, a blank coin with no design, may have been left behind, resulting in extremely rare and valuable 1943-S bronze pennies. In 2016, one of these pennies sold at auction ...

This 1984 $1 coin was struck on 10 cent blank error, making it a rare and valuable find. · Source: Roxbury's Auction House/Getty An “exceptionally rare” $1 ...