Doug Winter: The following information is from my eBook on Type One Liberty Head Double Eagles at http://doubleeaglebook.com/
The 1850-O double eagle is historically significant as the first double eagle produced at a branch mint. For many years, it was regarded as a common date. As the Type One series has become more popular and better researched, collectors have learned that the 1850-O is in fact a condition rarity which is hard to find above Extremely Fine-45, especially with natural color and choice surfaces. The 1850-O is very scarce in properly graded About Uncirculated-53 to About Uncirculated-55, rare in the higher ranges of this grade and extremely rare in Uncirculated.
STRIKE: The 1850-O is not nearly as well struck as its counterpart from the Philadelphia mint. However, it is still better struck than other double eagles from this mint. On the obverse, the hair is mostly well defined, although on some the curls around the face are not fully defined. The border is usually weak and it is not unusual to see pieces with a weak date and stars which appear to have been lapped. The reverse shows a similar pattern of strike with the center sharper than the periphery.
SURFACES: This is an extremely difficult issue to locate with choice surfaces. Nearly all 1850-O double eagles have extensively abraded surfaces from heavy use in local commerce. I would say that well under 10% of all known examples have below average quality surfaces with most showing deep, detracting marks in the fields on both sides. Choice, lightly marked pieces command strong premiums among knowledgeable collectors or dealers.
LUSTER: Most 1850-O double eagles are worn to the point that they show little natural mint luster. On higher grade examples, the luster is not especially good and it tends to display a grainy sort of texture. There are a few higher grade examples which have nice frost and these are extremely rare.
COLORATION: The natural coloration is medium to deep greenish gold. A few original coins are seen with subtle golden-orange shades. It is very hard to obtain an 1850-O double eagle with good color. A hoard numbering 50-100 entered the market in the mid-1990’s and these were characterized by dark (sometimes unappealing) color with black smudges often seen in the fields and on the relief details. It is extremely hard to find a choice, original 1850-O with pleasing natural color.
EYE APPEAL: This is an extremely hard date to find with good eye appeal. Many are not well struck and most have very heavily abraded surfaces. The small number which do have good eye appeal can command very strong premiums when they trade among knowledgeable specialists.
INTERESTING VARIETIES: As on the 1850 Philadelphia double eagles, varieties are known with an Open 5 and a Closed 5. These are not of interest to Type One collectors.
PROOFS: No Proofs were struck this year.
HOARDS: As mentioned above, approximately 50-100 pieces entered the market in the mid-1990’s from an overseas source. There were 10 in the S.S. Republic treasure, including one in MS60.
BUYING TIPS: This is a much harder issue to locate with good eye appeal than most collectors realize. I would strongly suggest that if you see a really pleasing example which is in your price and grade range, do not hesitate to buy it as these are really few and far between.
AUCTION RECORD: The current auction record for this date is $111,625. It was set by Heritage 6/14: 4048, graded MS61 by PCGS.
FINEST KNOWN: This is a difficult issue to definitively state which specific coin is the finest known. The highest graded at PCGS is an MS61 which sold for $111,625 as Heritage 6/14: 4890, but I have seen at least two or three others in lower grade holders which I liked better. Two PCGS AU58’s are real standouts: the example in the Crawford collection (likely ex Dallas Bank collection), and an example in a New England collection which was obtained from me via private treaty.
TOTAL KNOWN: 600-800
Very Fine: 239-320
Extremely Fine: 300-400
About Uncirculated: 58-76
POPULATION FIGURES: As of the beginning of 2015, PCGS has graded just a single coin in Uncirculated: an MS61. NGC has graded two in MS60, two in MS61, and one in MS62, as well as an MS60 from the S.S. Republic for a total of seven in Uncirculated. CAC has approved just one Uncirculated coin, graded MS61.
PERFORMANCE SINCE 2002: In 2002, it was possible to obtain a decent quality AU example of this date in the $4,000-6,000 range. Today, such a coin costs $12,500-25,000+.
COMMENTS: The rarity and significance of the 1850-O double eagle has become more widely known in the last few years. Most of the examples which I have seen in AU50 to AU55 holders by both major services are marginal quality at best, and properly graded mid-range AU’s with good eye appeal are very hard to locate. In the last five years I have seen maybe three to five properly graded AU58’s, and each of these sold quickly to serious collectors. When I wrote the first edition of my New Orleans book (all the way back in 1992!) this was an inexpensive, lightly regarded issue, and I think my writings over the last two decades have contributed in the new appreciation that the 1850-O now receives.
David Akers (1975/88): The 1850-O is very scarce in all grades although, from the standpoint of total number of specimens known, it is the third most common Double Eagle from the New Orleans Mint. (The 1851-O and 1852-O are the two dates that are more common.) Virtually the entire known population of 1850-O Double Eagles grades VF or EF and strictly graded AU's are quite rare. In full mint state, the 1850-O is excessively rare, if not unknown. In high grade this issue is on a par with most of the other early O-Mint issues, and is actually more rare than the highly touted 1879-O. I have personally examined two borderline uncirculated (AU55+) specimens but have not seen a true unc. Acording to rarity by average grade, the 1850-O ranks 4th out of the entire 204 coin Double Eagle series. Every specimen that I have seen was either semi-prooflike or fully prooflike.