Description :

* 1915 Indian Head $2.50 Gold Quarter Eagle

* Denomination: $2.50 (Quarter Eagle)

* Date: 1915

* Mint: Philadelphia — no mint mark

* Designer: Bela Lyon Pratt

* Composition: 90% gold, 10% copper

* Diameter: 18 mm

* Edge: Reeded

* Gold content: approximately 0.12094 troy oz. of pure gold

* Mintage: 606,000 circulation strikes

* Design: Incuse (the design is recessed into the surface rather than raised)

* Obverse: Native American portrait wearing a feathered headdress, with LIBERTY above and 1915 below

* Reverse: Standing bald eagle with UNITED STATES OF AMERICA, E PLURIBUS UNUM, IN GOD WE TRUST, and 2 1/2 DOLLARS

* 1915 was the last year of the first production period for the Indian Head Quarter Eagle; the series was then suspended until 1925. 

One particularly cool piece of history

These $2.50 coins are unusual because of their incuse design. On ordinary coins, the portrait and lettering stick up from the surface. On this coin, they're pressed down into it. The U.S. Mint specifically describes the technique as an ancient form of relief sculpture, and it was an unusual experiment in modern American coinage.