The crescent moon embroidered in black thread on a cloth background featuring the Universal Camouflage Pattern is authorized for wear by Muslim Chaplains on the Patrol Cap and Sun Hat.
While members of the Chaplain Corps most certainly are Officers and hold the same sort of ranks as Officers in each branches of the Army, they are not allowed to display their rank insignia on the Army Combat Uniform or other Utility uniforms and uniform items. Rather than a Lieutenant Colonel’s oak leaf, for example, the Chaplain might wear a cross insignia indicating a Christian faith or a Crescent moon indicating Muslim beliefs and practices.
The issue of Chaplains wearing insignia of rank has cropped up time and again for the Army. In 1864, the Army created the rather unique “rank of chaplain without command,” then modified it to the “assimilated” rank of Captain—i.e., they were supposed to be treated as Captains while not being given the authority to act like them. At the start of the 20th century, it appeared that the notion of command authority and rank would be introduced into the Chaplain Corps when, in 2004, the Army announced that Chaplains with ten years of service were being promoted to Major. And in 1914, Chaplains began to wear Officer insignia.
This ended abruptly in 1918 as the result of the beliefs of AEF Commander John J. Pershing and AEF Chief of Chaplains Bishop Charles Brent. Both men felt that Soldiers’ perceptions of rank would harm the relationship between Soldiers and the men from whom they were seeking guidance, counseling, advice.
But the Army’s first Chief of Chaplains, Colonel John Axton, reversed this decision and in 1926 Chaplains once again wore rank insignia. Today, you’ll see that rank insignia in all the usual places save one: headgear.