The fifty-cent coin was first introduced as a .900 purity silver half dollar in 1866. These coins were 13.41 grams, with a diameter of 32 mm, thickness of 2 mm, and a reeded edge. The design was similar to the British trade dollar, except the image of Britannia was replaced by Queen Victoria. The dates of issue were 1866-67 with only 59,000 issued for both dates combined. Mintage years are as follows: 1951, 1958, 1960–61, 1963–68, 1970–75, 1977–80, 1990, 1993–95, 1997-98 and 2015.