Georgia state quarters from 1999 have several types of error. The biggest error involves coins struck on experimental metals, called planchets, intended for the Sacagawea dollar.
As U.S. Coins Guide noted, the Georgia and other state quarters were minted in 1999 when the U.S. Treasury first began the state quarters program.
This took place just as the U.S. Mint was working on a new metal alloy for coins. The alloy had a gold tint that was eventually used for the one-dollar Sacagawea coins that came out in 2000.
“Curious how the alloy would look on quarters, a bunch of Georgia state ones were minted using it,” the U.S. Coins Guide said in a blog.
“The Treasury decided not to go with the alloy on quarters, but the ones minted with it were still released and are now very much desired by collectors.”
Signs of an experimental planchet 1999 Georgia quarter error: – On a coin scale, weighs 5.9–6.3 grams, compared to 5.67 grams for a copper-nickel quarter.
– Appears thicker than normal – Has a golden or greenish color, similar to Sacagawea dollars – Lacks the copper (orange-colored) stripe on the edge of the coin