This coin is commonly called the "Mercury" dime, although the representation is actually that of Liberty wearing a winged cap.   According to the Red Book, 2009 the wings are to represent liberty of thought.

The designer of this coin is Adolph A. Weinman; it weighs 2.5 grams, and is composed of 90% silver and 10% copper.

The mint marks (D for Denver and S for San Francisco) appear on the reverse (back) of the coin, to the left of the column.

There are very few true "key" dates in this series, among them are the 1916 D, the 1921 P and 1921 D.  There are two over strike coins which are seldom seen outside of collections, and those are the 1942, with the 2 over the 1 and the 1942 D, with the 2 over the 1.

"Semi-Key" dates are 1913 S, 1926 S.

These coins are available in $1000 face "bags", at a considerable premium over other types of 90% coinage. There are 10,000 pieces in a $1000 face bag.