The Institute of Heraldry has no information regarding the origin of the 312th Support Group Distinctive Unit Insignia (unit crest), its history, or the meaning of the symbols used on it. However, there are a few things we can know about the unit for which this design was originally approved.
First, the keystone at the top of the insignia denotes that the unit was activated or stationed for a considerable length of time in the state of Pennsylvania, or perhaps that a majority of its original members were from that state.
The black design in the middle is a millrind, longtime heraldic image indicating support. On either side of the millstone are sheafs of wheat, indicating the unit had some responsibility in providing sustenance to troops. The gold background is the color of excellence.
“Serve Support Supply” simply reinforces the imagery and the unit’s role as a Support unit.
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Also known as a unit crest or DUI, a Distinctive Unit Insignia is worn by all Soldiers (except General Officers) in units that have been
authorized to be issued the device. It is worn centered on the shoulder loops of the Army Green Service Uniform (AGSU) and the blue Army Service Uniform (Enlisted only) with the base of the insignia toward the outside shoulder seam. DUIs are not worn on the Dress variations of either uniform, however.
Enlisted personnel wear the insignia centered on a shoulder loop by placing it an equal distance from the outside shoulder seam to the outside edge of the shoulder-loop button. Officers (except Generals) wearing grade insignia on the shoulder loops center the DUI by placing it an equal distance between the inside edge of the grade insignia and the outside edge of the button.
Full guidance on wear of the DUI is found in DA Pamphlet 670-1,
Section 21-22, "Distinctive unit insignia" and 21–3(d) and (e),
"Beret" and
"Garrison Cap," respectively.