By CoinWeek Staff Reports …..
A 1970-S Kennedy Half Dollar Proof described as a “unicorn” coin has sold on eBay for a staggering $19,995. Does this price make sense? Let’s talk about it.
The 1970-S Kennedy Half Dollar Proof is the final Proof issue of the short-lived 40% silver era of Kennedy Half Dollars. These precious metal coins were struck from 1965 through 1970–both for circulation and for collectors–immediately following the removal of silver content from America’s circulating coins.
The United States Mint reported sales of 2,632,810 1970-S Proof Sets. These sets were sold at an issue price of $5.00 ($42.02 in 2025 inflation-adjusted dollars) and today sell for about $13 intact. A certified 1970-S Kennedy Half Dollar typically sells for under $30, unless the coin is described as having Deep Cameo/Ultra Cameo (not all Proofs of this period exhibit frosted devices).
So what gives?
We believe that the seller was able to find a taker based on three factors: PCGS certification, monster rainbow toning, and an over-enthusiastic buyer.
The PCGS Angle
PCGS certified this coin PR67 during its “rattler” holder period. Judging by the color of the insert and the presence of four alignment pins, we place the certification of this coin between February 1986 and September 1989. The grade of Proof 67 is typical for the date. When the coin was certified, PCGS was applying designations for Cameo and Deep Cameo contrast, and the coin appears brilliant, like most Proofs of the era.
What we do not know is whether the coin had this extreme toning when it was certified or whether it developed this color in the holder. Rattler holders are not airtight, so it is possible that the coin turned over time. If it did, however, one has to wonder whether the coin might have been gassed to achieve its color. The seller has 98.7% positive feedback and offers many coins with toning. These all appear to be legitimate, which lends credibility to the $19,995 1970-S having natural toning.
Monster Rainbow Toning
Let’s assume that this toned 1970-S Kennedy Half Dollar Proof is natural. How does the market treat this coin? We can say from experience that dealers will always charge premium prices for coins with PQ toning. They tend to be scarce and give coins a unique character that increases their eye appeal. Because collectors are willing to pay significantly higher sums for these coins, collectors and dealers with knowledge of coin chemistry have an incentive to add color to coins. This is not a new problem, but coin doctoring techniques continue to evolve and improve. We keep bringing this up because the market has to believe that the toning is genuine and exceptional for the coin to warrant its high price tag.
In this case, we believe that the buyer took a leap of faith and that the seller believed the toning is natural.
Coins with toning of this caliber often sell for multiples of the price of non-toned examples. When Legend Rare Coin Auctions sold the Northern Lights Collection of Toned Morgan Dollars, the prices realized were often 10x or greater than the date would have realized if the coins had so-so toning or were blast white. For that collection, Legend’s Laura Sperber gave each of the coins names like “Wavy Gravy”, “Blazing Saddles”, and “Purple People Eater” based on how she interpreted their color. Collectors ate the coins up!
In this listing, eBay seller cstergion describes the 1970-S Kennedy Half this way:
This is the infamous Unicorn Kennedy proof. It is one of a kind and amazing. The coin is golden toned with rainbow colors front and back. It is especially rare being that it is an early holder and has the craziest color I’ve ever seen on any proof coin.
The keywords from this description are: “unicorn”, “one-of-a-kind”, “amazing”, “especially rare”, “early holder”, and “craziest color I’ve ever seen”. This description undoubtedly helped the seller close the deal.
A Case of an Over-Enthusiastic Buyer
Is the $19,995 sale of a 1970-S Kennedy Half Dollar monster toner evidence of an over-enthusiastic buyer? This is a hard question to answer.
For starters, the eBay seller does not appear to exorbitantly overprice their coins – even certified coins with rainbow toning. This leads us to conclude that they truly believed in the coin and priced it at a level they were willing to hold onto it at until they got their price. There are no public auction records of a 1970-S Kennedy Half Dollar selling at this level, and PCGS reports no transactions over the $805 paid for a Proof 69 sold by Heritage in 2008.
GreatCollections does not provide PCGS CoinFacts its auction API, but doing a manual search, we found this NGC PF69UCAM that sold on January 10, 2021 for $960.75. Both the Heritage and GreatCollections Kennedy Halves were brilliant, which makes for an inexact comparison with this “unicorn”. Nevertheless, for a toned 1970-S Kennedy Half Dollar coin to shatter the previous public auction record by a factor of 20x is remarkable.
Time will tell whether this buyer comes to regret their $19,995 purchase. In a few months, the eBay listing will drop off their advanced search, and the only public record of the sale will be this article. Will that be enough for the seller to break even or turn a profit? Was that even the goal in the first place?
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