The gold and silver color bars found on today’s Chief Warrant Officer insignia in the United States Navy trace their origins back to 1886, three years after the Navy gave Warrant Officers specific corps or specialty devices for the first time. To determine the grade of a Warrant Officer, the Navy used a very broad standard: those with 20 or more years or service wore a gold device, while those with less than 20 wore silver.
This bifurcated system lasted until the passage of the Career Compensation Act in 1949 established four grades of Warrant Officers in the Navy: Warrant Officer 1, and Chief Warrant Officer 2, 3, and 4. For the insignia of grade to be worn on caps and collars, the Navy turned to its previous system of silver and gold, with silver indicating seniority—or, in the new scheme, a higher rank—over gold; to accommodate the four grades, the Navy implemented double bars that indicated higher rank than a single bar.
Thus a single gold bar is the insignia of grade for the rank of Warrant Officer 1—but it isn’t an insignia that is seen among active-duty personnel any longer. The Navy eliminated the grade completely in 1978, commissioning new officers at the grade of Chief Warrant Officer 2; nearly 25 years later, it would add the grade of CWO5 to bring the total number of Navy Warrant Officer grades back to four.