Images courtesy of

Recent appearances:
NGC MS-61 (illustrated above).  Ex - Superior Galleries' "Pre-Long Beach Sale" May 27-29, 2001, Lot 4251, where it was described as follows: "Gold1853 United States Assay Office of Gold. $20. 900 THOUS. NGC graded Mint State 61. The Assay Office struck gold coins and slugs in varying alloys, this being standard coin alloy of 90%, although the yellow-gold color suggest more silver in the 10% than copper, unlike coins made by the federal mints which were supposed to be 10% copper alloy only. The coin has a wonderful frostiness to it, everywhere including the well-defined eagle. The eagle is handsomely displayed on the obverse, its wings outstretched, holding in its beak a ribbon that is inscribed LIBERTY in raised letters. At its feet, a shield, while in its claw it grasps three arrows. The reverse contains a fancy design with rectangular tablet in the middle inscribed with UNITED STATES ASSAY OFFICE OF GOLD SAN FRANCISCO CALIFORNIA 1853."

About Uncirculated.  Ex - Stack's "65th Anniversary Sale", October 17-19, 2000, Lot 1968, "K. 18, .900 THOUS."

Choice Extremely Fine with claims to About Uncirculated.  Ex - Stack's "65th Anniversary Sale", October 17-19, 2000, Lot 1969, "K.18, .900 THOUS., The .900 THOUS over the eagle testifies that this USAOG coinage had been raised to the full .900 fineness mandated by Federal law.  This type and date also exist with fineness of .884 THOUS."

Sources and/or recommended reading:
"Private Gold Coins and Patterns of the United States" by Donald H. Kagin