Charles Barber's goloid designs of 1879 now dated 1880. Goloid was an alloy patented by Dr. Wheeler Hubbell and consisted of gold, silver and copper in various proportions. They were used in an attempt to make the silver dollar smaller and lighter and in the creation of the famous $4 gold piece or Stella for use as an international coinage. For additional information on the Stella, click here.
It is unclear if the dollars and Stella were actually struck using the goloid alloys or are of standard silver and gold. Over a dozen sets were produced in silver/goloid. Additional sets were also produced in copper (over a dozen) and aluminum (4 or 5).
George T. Morgan also produced a set. To view, click here.
Photos courtesy of Heritage, Ira and Larry Goldberg's Coins and Collectibles and Bowers and Merena