The half union (separate varieties known as J-1546 through J-1549[1]) was a United States pattern coin with a face value of fifty U.S.

In 1877, famed Chief Engraver of the Mint at the time, William Barber, designed the coin.

William Barber also designed several other coins, such as the "Amazonian Quarter" pattern, the short-lived Twenty Cent Piece, and the Trade Dollar.

As it is a pattern, it was never struck for circulation and all other known presentation versions were made of copper or sometimes various gilded metals.

The 1959 film Rio Bravo includes several references to $50 gold pieces, even though none were ever issued for circulation.