Shield
Azure, on a fess wavy between three fleurs-de-lis, one and two, Argent four lozenges conjoined Gules.
Crest
That for the regiments and separate battalions of the Army Reserve: On a wreath of the colors Argent and Azure, the Lexington Minute Man Proper. The statue of the Minute Man, Captain John Parker (H.H. Kitson, sculptor), stands on the common in Lexington, Massachusetts.
Motto
AU FEU TOUJOURS (Always At The Fire).
Shield
The shield is blue for Infantry. The wavy fess represents the Aire River in France, which the organization crossed 16 October 1918, after desperate fighting. The three fleurs-de-lis symbolize the two major operations and defensive sector. The four lozenges are taken from Sir George Carteret's coat of arms, denoting the allocation of the organization to New Jersey.
Crest
The crest is that of the United States Army Reserve.
The coat of arms was originally approved for the 312th Infantry Regiment on 28 August 1930. It was redesignated for the 312th Regiment on 4 December 1959.