The following information is from my eBook on Type One Liberty Head Double Eagles at http://doubleeaglebook.com/
The 1859 has the second lowest mintage figure of any Type One double eagle from the Philadelphia mint. Not including the exceedingly rare 1861 Paquet, it is the second rarest Philadelphia Type One in terms of overall rarity and it is actually the rarest in higher grades, narrowly surpassing the 1862.
A slight design change occurred on double eagles beginning with this issue. A new obverse hub was used which showed the designer’s initials (JBL; for James Barton Longacre) further to the left on the truncation. In addition, the truncation was slightly more curved and the curls around the bun and below the ear of Liberty were slightly modified.
STRIKE: This is a relatively well-struck issue. On the obverse, the hair detail is fairly bold with the curls around the face and below the ear showing some individual definition. The stars at the left are sometimes flat while those above the head of Liberty and to the right are sharper, sometimes with full radial lines. The reverse is well-detailed with the exception of the tail feathers and the wing tips which are usually soft. There is often a network of fine cracks through the obverse stars.
SURFACES: With the possible exception of the 1866-S No Motto, the 1859 is the hardest Type One issue to find with clean surfaces. Virtually all known examples are extensively abraded with deep, detracting marks. These marks are often clustered in the left obverse field and on the face of Liberty and they severely detract from the overall eye appeal. Any higher grade piece with minimal marks is worth a very strong premium over a typical quality 1859 double eagle.
LUSTER: Most show luster which is frosty in texture. A smaller number are semi-prooflike. The quality of luster on the higher grade 1859 double eagles that I have seen tends to be good, but the average piece has impaired luster from past cleanings and the above-referenced marks.
COLORATION: The natural coloration is rose-gold with orange or greenish-gold undertones. As recently as a decade ago, the collector could find an 1859 with nice natural color, but these coins are either in tightly-held collections or they have been fiddled with by dealers.
EYE APPEAL: The level of eye appeal is well below average.
INTERESTING VARIETIES: A small number of 1859 double eagles show a repunched 18 in the date. This variety is interesting, but it is not considered collectible by specialists.
PROOFS: 80 Proofs are believed to have been struck. If this is accurate, most were melted. Proof 1859 double eagles are extremely rare and it is likely that no more than six or seven are known, including at least one which is impaired. Two others are impounded in museum collections.
As of the middle of 2014, PCGS has yet to grade an 1859 in Proof. NGC has graded one in PR58, one in PR62 Ultra Cameo, two in PR63 Cameo, one in PR65 Ultra Cameo, and one in PR66 Cameo for a total of six. This figure is likely slightly inflated by resubmissions.
HOARDS: A single MS60 was found in the S.S. Republic. In the late 1990’s, a group of three or four higher grade (MS60 to MS61) examples came onto the market. I am not aware of the source of these coins.
BUYING TIPS: If you are an ultra-finicky collector you will have to relax your standards when it comes to this date. A nice Extremely Fine or About Uncirculated with natural color and unmolested surfaces is very rare and you can expect to “pay up” for such a coin if you are lucky enough to be offered one.
AUCTION RECORD: The current auction record for a business strike 1859 is $37,375 set by Heritage 2004 ANA: 8460, graded MS62 by NGC. However, I have sold two coins in excess of this figure and I know of at least one other private treaty sale of over $50,000.
FINEST KNOWN: The finest known business strike 1859 double eagle is almost certainly the PCGS MS62 in the William Crawford collection. There are likely three or four clustered in the MS61 range, and these include one in a New England collection, as well as the NGC MS62 mentioned above.
TOTAL KNOWN: 250-300
Very Fine: 60-80
Extremely Fine: 100-120
About Uncirculated: 84-92
POPULATION FIGURES: As of the beginning of 2015, PCGS has graded two examples in MS61 and one in MS62 for a total of three in Uncirculated. NGC has graded three in MS60, three in MS61 and one in MS62 for a total of seven in Uncirculated. These figures have remained totally unchanged in more than five years and are likely not inflated by resubmissions. CAC has not approved any Uncirculated examples.
PERFORMANCE SINCE 2002: In the current market, a choice Extremely Fine example of this date (equivalent to EF45) is worth $6,500-7,500. In 2002, the same coin was worth $2,500-3,500. In the current market a nice quality About Uncirculated example of this date (equivalent to AU55) is worth $14,000-16,000. In 2002, the same coin was worth $5,000-6,000. While the price performance of this date has been very good in the last dozen years, in my opinion, it remains undervalued in virtually all circulated grades
COMMENTS: I used to rank this as the fourth-rarest Type One issue from Philadelphia, but I now feel that it is the rarest, both overall and in high grades. It is usually found in the Extremely Fine-40 to About Uncirculated-50 range and most coins which grade as such are low end. The 1859 double eagle is rare in properly graded About Uncirculated-53 to About Uncirculated-55, very rare in About Uncirculated-58, and extremely rare in Uncirculated.
David Akers (1975/88):
Along with the 1855-O, the 1859 is one of my "pet" dates of the first type of Liberty Head Double Eagle. The mintage is small but still does not begin to convey the true rarity of the date, particularly in high grade. In 443 auctions dating back over 60 years, only one 1859 was ever catalogued as "uncirculated," the Holmes specimen in 1960. I have not seen that particular coin and thus cannot say whether or not it was really uncirculated. I can say, however, that I have never personally seen an unc and have seen no more than a few that legitimately graded AU. The finest I know of was in Paramount's 1974 Greater New York (May) Sale. The typically available 1859 is well worn, usually VF with a partially prooflike or fully prooflike surface. Actually, in any grade the 1859 must be considered rare. Among all 204 Double Eagle issues, it is tied for 7th in rarity according to average grade and is just below the top 20 (25th) based on total number of appearances at auction.