Uniform of the Union Army letters US. Officers, NCOs and cavalry troopers were equipped with a sword belt with a rectangular buckle with eagle motif. Rank was displayed on epaulettes (dress occasions) or shoulder straps(field duties): no insignia for a second lieutenant, one gold bar for a first lieutenant, two gold bars for a captain, a gold oak leaf for a major, a silver oak leaf for a lieutenant colonel, a silver eagle for a colonel and one, two or three silver stars for a general, depending on his seniority. The color of the shoulder strap fields – with trims in gold braid – were
United States Army officer rank insignia In 1851, it was decided to use only silver eagles for colonels, as a matter of economy. The silver eagle was selected based on the fact that there were more colonels with the silver eagle that those with gold, primarily in the cavalry and artillery, hence it was cheaper to replace the numerically fewer gold ones in the infantry. At that time on the shoulder straps, lieutenant colonels wore an embroidered silver leaf; majors wore a gold embroidered leaf; and captains and first lieutenants wore gold bars. The second lieutenant had no grade insignia, but the presence of an epaulette