1852 United States Assay Office of Gold. $50 gold slug. K-14, B-7716. EF-45 (PCGS). Rarity-5.    Lustrous warm yellow gold. Quite well struck, better than usually seen. Obverse inscription near rim fully readable. A few small planchet fissures are seen here and there. An attractive, significantly above average example of this famous coin.
1852 U.S. Assay Office of Gold Fifty Dollar "Slug" 900 THOUS.
1852 United States Assay Office of Gold. $50 gold slug. K-14, B-7716. EF-45 (PCGS). Rarity-5. Lustrous warm yellow gold. Quite well struck, better than usually seen. Obverse inscription near rim fully readable. A few small planchet fissures are seen here and there. An attractive, significantly above average example of this famous coin.

Details
1852 United States Assay Office of Gold. $50 gold slug. K-14, B-7716. EF-45 (PCGS). Rarity-5. Lustrous warm yellow gold. Quite well struck, better than usually seen. Obverse inscription near rim fully readable. A few small planchet fissures are seen here and there. An attractive, significantly above average example of this famous coin.
Further details
Die notes: Dies similar in motif to the following, but with 900 THOUS. on cartouche above eagle. Die state: Perfect dies. PCGS Data: This is the only example from the S.S. Central America treasure certified by PCGS.The Mint Standard The federal standard for gold coinage was 900 fine, consisting of 900 parts gold and 100 parts alloy, typically copper, but a small amount of silver was allowable. Although some native California gold was significantly above 900 fine, most was below the federal standard. It was relatively easy for the U.S. Assay Office of Gold to alloy metal and achieve finenesses of 880, 884, and 887, but seems to have been almost a logarithmic jump to 900, involving more effort, a larger quantity of parting acid, etc. For this reason, relatively few 900 fine coins were made, and these did not appear until 1852.