“They were hidden for decades.” Russell said. “Most major collectors and dealers have never seen one.”
The mint in San Francisco made more than 2.8 million special uncirculated “proof” sets in 1975 that featured six coins and were sold for $7. Collectors a few years later discovered that two dimes from the set were missing the mint mark.
The sisters from Ohio who inherited one of those two dimes after the recent death of brother want to remain anonymous given their sudden windfall, Russell said.
They shared with Russell that their brother and mother in 1978 bought the first error coin discovered for $18,200, which would amount to roughly $90,000 today. Their parents, who operated a dairy farm, saw the coin as a financial safety net.
One of the sisters said her brother often talked about the rare coin. But she never saw it first-hand until last year.