All five branches of the United States Armed Forces authorize the wear of tie tacks or tie clasps featuring insignia of grade by officers wearing long ties that meet their service's uniform regulations and standards.
In the United States Armed Forces, the officer pay grade of O-7 includes the ranks of Brigadier General (Air Force, Army, Marine Corps) and Rear Admiral, lower half (Navy and Coast Guard) and employ the same rank insignia found on this tie tack / clasp: a single star. The single silver star was first introduced into the United States Military in 1780 when Continental Army Commander-in-Chief ordered Major Generals to wear two silver stars on their epaulets and Brigadier Generals to wear just one. Washington’s proclamation came five years after Congress had first established those two ranks—and it would take several decades more before equivalents ranks would be established in any of the other branches of the military.
The first non-Army General in the U.S. military was the Marine Corps' Archibald Henderson, who received a brevet promotion to Brigadier General in March 1843 (effective from January 27, 1837). Now known as the “Grand old man of the Marine Corps,” Henderson was appointed Commandant of the Marine Corps 1820, and his actions as a commander in the Indian Campaigns in Florida and Georgia in 1836-1837 were what ultimately led to his promotion. (Commandant Jacob Zeilin was the first Marine to receive a non-brevet promotion to Brigadier General in 1874.)
From its inception, the United States Navy had been leery of adapting the rank title of “Admiral” because of the rank’s close association with European navies and their traditions. But following Command David Farragut’s capture of the port city of New Orleans in 1862, Congress put the Navy’s qualms aside and named him the service’s first Rear Admiral; he would later go on to become the Navy's first Vice Admiral and, in 1866, its first full Admiral.
It took even longer for the Coast Guard to see one of its officers reach the one-star rank of Rear Admiral, but this comes as no surprise since the Coast Guard as we know it did not even come into existence until 1915. In 1923, Congress passed an Act that promoted Coast Guard Commandant William E. Reynolds to the rank of Rear Admiral.