The rare coin is one of only two known 1975 proof set dimes mistakenly made without the San Francisco Mint’s signature “S” mint mark. For decades, the dime was kept as a safety net by an Ohio family who recognized its unique value. After inheriting it from their brother, three sisters found themselves with a valuable piece of American coinage history and the desire to finally sell it at auction.
What Makes This Coin So Valuable?
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This rare coin, a 1975 proof set dime, stands out due to an error: It was struck without the “S” mint mark, which signifies the San Francisco Mint. This mint mark is typically essential on proof coins made in San Francisco, making the absence of the “S” on only two dimes extraordinarily rare. This rarity boosted the value of this error coin, leading it to sell for a whopping $506,250 at auction.
Why Is the Error So Significant?
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In 1975, the San Francisco Mint created over 2.8 million proof sets of coins, yet only two known dimes from that batch are missing the “S” mint mark. This kind of production error is extremely rare, particularly for proof sets, which are produced with precise standards. The “no S” dimes became highly coveted among collectors; the other dime sold at auction in 2019 for $456,000.
How Was the Coin Discovered?
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Three sisters from Ohio inherited the rare coin after their brother, who stored it in a bank vault for over 40 years, passed away. The siblings were unaware of the coin’s exact location until recently. The brother and their mother purchased the dime in 1978 after learning about its rarity, paying $18,200 — equivalent to about $90,000 in today’s dollars.
How Did the Family Sell the Coin?
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The coin went up for sale at GreatCollections, an auction house in Irvine, California. It fetched over $500,000 after the online auction concluded on October 27. GreatCollections president Ian Russell confirmed the sale, highlighting how sought-after the “no S” proof dime had become since collectors learned of its existence in the late 1970s.
The Family Safety Net
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The Ohio family who owned this coin viewed it as a potential fallback if their dairy farm faced hardship. Their purchase of the error coin in the late ‘70s was a calculated move, preserving it for decades as a form of financial security (proven by its protected location in a vault). This perspective came full circle when the coin sold for more than half a million dollars, offering a substantial financial gain for the sisters who inherited it after an initial investment of less than $20,000.
