Hi Karen,

Thank you for contacting Mearto with your appraisal inquiry.

There was no official US dime minted in 1988 made of copper; the 1988 dime featuring Franklin Delano Roosevelt was first issued in 1965 and had a 100% copper core and outer layers comprised of 75% copper and 25% nickel. What you're seeing is probably wear to the nickel, which is not unusual.

There are no widely recognized or documented mint errors where a dime was struck on a pure copper planchet. Wrong-planchet errors do exist in U.S. coinage, but a confirmed 1988 copper dime would be extraordinarily rare and well-known.

The Roosevelt dime minted in Denver Mint in 1988 (the 1988-D dime) had a mintage of 962,385,489 (nearly 1 billion) coins. Only those in exceptional condition or mint errors (virtually unknown) bring meaningful value to this coin.

If you went to the trouble and expense of having this authenticated by a reputable third-party grading service who determined this was a wrong-planchet error, this could be worth thousands. As it's more likely to be simply a worn dime, it doesn't have any value more than it's face value, or ten-cents.

Based on the photos and information provided, and subject to examination, this is:

A 1988 Denver-minted FDR dime
in ungraded (but worn condition)
.4 inches
CONDITION: worn
PROVENANCE: unknown
ten cents*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, or questions/concerns, and thank you again for using Mearto.
~ Delia