What a beautiful piece I personally don’t know what it is but I’d love to have it lol Research it anyway you can that’s what’s fun about this hobby congratulations Alabama
It appears to be one of these, said by the seller to be vintage US Army.
I don’t know how reliable that might be, nor which sections of the US Army might have used this insignia if it is correct. However, the badge was made by Ira Green Inc. (IGI) founded in Providence, Rhode Island in 1943 and they are the largest manufacturer and distributor of US military decorations, medals, insignia and uniform related accessories.
This turns out to be pretty obscure, but it's a US Army Unit Crest for the 46th Engineer Battalion. What looks like a sword is in fact a "steel spike", which is also the unit's nickname.
Nice find! It's like a lot of U.S. Army small units, if you weren't in it or directly involved with it, you probably aren't familiar with that unit! Yes I was U.S. Army 1966-68. Not in that unit, or involved with it.