Question: I have just bought a 1921-S Morgan dollar, MS-63, and find that it has a microscopic S mintmark. I cannot find a listing for such a mintmark size, although I know there is a 1945-S “Micro S” Mercury dime. Do I have a rarity?
Answer: All 1921-S Morgan dollars have very tiny mintmarks, much smaller than on the S-Mint dollars of the 1878-1904 years. As they are all the same size — albeit “micro” — no special notice of them has been taken in price listings. The 1921-D dollars have tiny mintmarks as well.