David Hall: The Smithsonian example is a 45/50 coin, and very attractive for the grade.David Akers (1975/88): Without question this is one of the rarest and most famous of all Double Eagles. It is by far the rarest CC-Mint twenty and it is surpassed in overall rarity among all regular issue Liberty Heads only by the 1861 Paquet, the 1856-O, and the business strikes of 1882 and 1886. The 1870-CC is similar in rarity to the 1854-O and business strikes of 1881 and 1885 and just a little less rare than the proof-only 1883 and 1884. From the standpoint of condition rarity, the 1870-CC is one of the rarest, if not the rarest, dates in the entire series. I have never seen a full AU and the typical 1870-CC is only F or VF with a heavily bagmarked, prooflike surface. Q. David Bowers has written that he handled a mint state 1870-CC many years ago and so that specimen is undoubtedly the finest known example of this rare date by a considerable margin.
The 1870-CC $20 combines extreme rarity, the allure of gold, a large size, and the lore of the Carson City Mint in a neat, tidy, and very expensive package. At least one expert believes that the surviving population numbers only 35-45 examples, but this seems low considering that PCGS alone has certified 34 coins (as of October 2014). Add in coins certified by NGC, subtract resubmissions and crossovers and the correct number of probably over 50 examples. Regardless, the 1870-CC $20 is under considerable pressure from collectors of the Liberty Head series, fans of the Carson City Mint, and anyone looking for a trophy coin.
This date is not known for being well struck; rather, a common complaint is that some or all of the obverse stars are flat. Most of the surviving population hovers around the XF45 grade, with few examples on either side, especially the higher side. Bowers (in his 2004 book, A Guide Book of Double Eagle Gold Coins) does not mention the Mint State example that Akers' claimed he reported, but he does price an MS60 example at $600,000, suggesting that such a coin exists. The price record for this date belongs to the NGC AU55 example that sold for $414,000 in 2009.
Doug Winter - Nevada Collection - Universal Coin and Bullion, sold privately in 1999 - Bowers & Merena 6/2002:2371, not sold - Heritage 1/2004:3129, $368,000 - Donald E. Bently Collection - Heritage 3/2014:30435, $411,250
Lee Minshull and Casey Noxon - James E. Haldan Collection - Sotheby's 6/1996:146 - Universal Coin & Bullion - Heritage 4/2014:5821, $305,500
Usibelli Collection - Heritage 1/2014:5541, $329,000