Die Struck pins,as its name made by die stuck.Solid and heavy metalic look.In different shapes,high or low 3D/2D relief.Usually made with iron materil,zinc alloy material or brass material.Brass material is most popular as can keep the color of brass itself without plating,also can plate into gold,silver,black...any other plating colors.

To keep the metalic look,then not fill or printing other colors on it.Simple but elegant.