The following information is from my eBook on Type One Liberty Head Double Eagles at http://doubleeaglebook.com/
The 1860-O is similar to the 1859-O in terms of its overall and high grade rarity. As with its counterpart, the 1860-O is a rare date in all grades and it has become next to impossible to find a choice, original example in just about any grade.
STRIKE: The 1860-O is not a well-struck issue. All known examples are weak on Liberty’s hair. There is a lack of detail on the curls around the face and below the ear of Liberty. The hair at the top of the head is sharper, and some higher grade pieces will show a strong bow. The first four stars on the left of the obverse are often flat with no radial line detail with the remaining stars are sharper. The denticles on the obverse are well defined. On the reverse, the horizontal stripes may show weakness and the tail feathers are usually weak as well. The wing tips are weak while the rest of the feathers are sharp.
SURFACES: Nearly every 1860-O double eagle which I have seen has been excessively abraded with deep, detracting marks. On some higher grade pieces, there may be little in the way of actual wear, but the surfaces are abraded to the point that PCGS or NGC will “net grade” the coin down to a lower level. This is one of the hardest Type One issues to locate with choice surfaces and a clean, reasonably mark-free example is worth a significant premium.
LUSTER: The luster seen on this date is better than on the 1859-O. Higher grade coins are usually semi-prooflike and a full are close to fully prooflike. The luster is nearly always interrupted by the aforementioned surface marks. There are a few known with especially good luster and these are visually impressive.
COLORATION: The natural coloration is a bit lighter than on the previous few issues from this mint. High-grade uncleaned pieces can show a very pleasing deep yellow-gold color which is not seen on many other New Orleans double eagles. Most 1860-O double eagles have been cleaned or dipped and this gives them a washed-out appearance. The few known which are CAC quality are seldom available for sale and one becomes available, it brings a significant premium over a typical example.
EYE APPEAL: This date has below average eye appeal. The typical piece is well worn, not well-struck, and is heavily abraded. Most have been cleaned or dipped and this gives them a washed-out appearance. It has been a while since I have seen a truly “PQ” example and I think a very choice high grade 1860-O would set a record price if offered for sale at auction.
INTERESTING VARIETIES: A single die variety is known.
PROOFS: No proofs were struck.
HOARDS: A single example was found in the S.S. Republic, but it was a remarkable MS60PL which is now regarded as the second finest known. In the early to mid-1990’s, a small group of lower grade pieces was found in Europe. These were quickly dispersed into the market.
BUYING TIPS: Since this is such a hard issue to find with choice surfaces, a buyer is going to have to be less concerned with marks and more concerned about originality and overall eye appeal.
AUCTION RECORD: The current auction record for this date was set by Heritage 10/08: 3030, graded AU58 by PCGS, which sold for $97,750. An NGC MS60PL has traded at least twice via private treaty and both times it realized a significantly higher price than the auction record for this date.
FINEST KNOWN: The finest known 1860-O double eagle is owned by Bill Crawford, and it is ex Eliasberg: 901 where it sold for $15,400. This coin is currently in a PCGS AU58 holder, but I have seen it in person and grade it at least MS61 to MS62. The second finest is the NGC MS60PL mentioned above.
TOTAL KNOWN: 85-95
Very Fine: 31-34
Extremely Fine: 30-33
About Uncirculated: 22-27
POPULATION FIGURES: As of the beginning of 2015, PCGS had graded eight in AU50, nine in AU53, five in AU55, and five in AU58 for a total of 27 in About Uncirculated. They have yet to grade a coin in Uncirculated. NGC has graded 10 in AU50, 13 in AU53, eight in AU55, two in AU58PL, and seven in AU58 for a total of 40 in About Uncirculated. They have also grade a single coin in Uncirculated, an MS60PL. These figures are significantly inflated by resubmissions, especially in AU53 and AU55. CAC has only approved three examples, the highest is an AU50.
PERFORMANCE SINCE 2002: In the current market, an average quality Extremely Fine example of this date (equivalent to EF40) would be worth in the range of $25,000-35,000. In 2002, the same coin would have been worth $10,000-15,000. In the current market, a choice About Uncirculated example of this date (equivalent to AU55) would be worth in the range of $55,000-65,000+. In 2002, the same coin would have been worth $17,500-22,500.
COMMENTS: The certified population figures for the 1860-O at both PCGS and NGC are very inflated and need to be severely adjusted downwards to represent a truer scope of the rarity of this date in properly graded Extremely Fine and About Uncirculated.
David Akers (1975/88):
All of the Double Eagles from the New Orleans Mint are scarce or rare, especially in high grade (AU or better), and the 1860-O is no exception; in fact, it is the third rarest of the 13 issues after the 1856-O and 1854-O. It is just slightly more rare than the 1855-O and 1859-O. The only specimen ever catalogued as uncirculated was the Atwater coin in 1946 (PCGS CoinFacts editor's note: After David Akers' book was written, the Eliasberg coin was catalogued and sold as uncirculated.) Not having seen that particular coin, I cannot state with certainly whether or not is was truly uncirculated. However, the famous Eliasberg Collection contains an unc and it may well be unique. I have also seen one AU-55 and a few others that graded AU-50. Still, VF and EF are the grades one is most likely to be able to find of this date and the 1860-O is so rare that it is not often available even in lower grades. According to rarity based on both average grade and frequency of appearance, the 1860-O ranks in the top 10% of the entire Double Eagle series. All of the specimens I have seen were partially or fully prooflike and the first four stars on the left obverse are always rather flat.