This is an example of a standard silver trident pin.
A silver trident is the emblem of the Trident Degree of Initiation. This degree was at first administered at the time of pledging, but when the 1912 Convention adopted a new member pin and a new pledge service, the Trident Degree became a formal degree administered a short time before the Stars and Crescent Degree.
This pin is silver and features a decorative trident at the top.