The 1918/7-S Standing Liberty Quarter is an extremely rare and popular overdate, especially in uncirculated condition. A single obverse die was overdated before producing an unknown number of the 11,072,000 Standing Liberty Quarters struck in San Francisco during the year.
The obverse die was created at the Philadelphia Mint where it was impressed once with a 1917-dated hub and subsequently with a 1918-dated hub. The die was then shipped to the San Francisco Mint where the mint mark was applied before the die was put into production. A similar variety was created during the same year for the nickel.
Despite the plainly visible appearance of the overdate, it was not discovered by collectors until nearly two decades after its creation. This results in very few surviving examples of the variety, particularly in uncirculated condition. For circulated examples, two diagnostics may be used to assist in identification. Genuine examples will display a die clash in the protected recesses near Liberty’s right knee, visible even in examples graded Good. The second diagnostic is a small pimple of extra metal above and the to the right of the final digit of the date. This diagnostic is less discernible on well circulated pieces.
A few high grade 1918/7-S Standing Liberty Quarters are graded MS66, however many collectors pursue the finest known pieces with the Full Head designation, graded MS64FH. One of the MS66 graded examples sold for $97,750 in January 2007. Some pieces graded MS64FH by NGC have sold for prices ranging from $40,000 to $50,000 in recent years.