Stack’s Bowers Galleries Coin Resource Center includes the complete catalog of Type III Saint-Gaudens double eagle dates, including the 1911-D and 1911-D/D. Though neither issue is especially rare or notable, the latter is the only overmintmark variety included in this catalog.
The Denver Mint produced 846,500 double eagles in 1911, a number of overmintmark varieties among them. TheCRC listing on the 1911-D/D offers this description of the doubling: “the engraver blundered the mintmark by moving the punch between solid hits, causing the D to be dramatically repunched.” Per The Cherrypickers’ Guide to Rare Die Varieties of United States Coins: “A secondary D mintmark is evident east of the primary D.”
The CRC’s descriptions of the 1911-D and 1911-D/D are brief but touch on the major points of collectability. The issues are relatively common, and the overmintmark variety does not command a significant premium, if any.
Like other CRC content, the listings covering Saint-Gaudens double eagles are broken down by series, subtype, strike (Circulation and Proof), and date.
The CRC is an evolving database, and we welcome any pertinent edits from knowledgeable readers.