The 1933 Double Eagle gold coin sold at an auction in New York on Tuesday
The coin was placed up for sale by designer and collector Stuart Weitzman, who bought it in 2002 for what was then a record price of $7.6million
It was the last gold coin stamped in the US but never went into circulation
The coin with a face value of $20 is the only one of its kind authorized for private ownership
Weitzman said he would use the money gained in the auction to fund his charitable ventures