Wow, Rick looks like I owe you an apology... I found a reference to your find in one of my relic books.
Turns out it is a half of an Armored Cod-piece from the uniform of a French Queen's Beret Regiment.
The Queen's Beret's were formed as a militia in 1859, in Paris, France. When the American Civil War broke out, they immediately petitioned the US Government to allow them to fight. Their requests were ignored until early 1862, when Lincoln over-ruled his staff and allowed them to join the Union Cavalry.
The Union Officers, under strict orders, tolerated their "peculiar" ways, but the enlisted men loathed them. Oddly enough, a large percentage of this Brigade were killed by friendly fire very early in the battles they participated in. This is owed to the fact that the backs of their bright pink uniforms were emblazoned with red & blue concentric circles, resembling a bullseye.
The Confederate forces positively despised them. Major Culp of the 17th SC wrote in his diary of the Queen's Berets: "This band of perverted scallywags do not deserve the honor of being called Damned Yankees!" As hard as the Union troops were on their so-called allies, the Confederates were nothing but brutal. Upon spotting these soldiers, (which was easy to do from a great distance due to the large fanned-out plume of dyed ostrich feathers protruding from their hind-quarters), the Southern forces tended to focus their fire upon them, sometimes with utter disregard for the battle at hand.
Culp also mentions a "point system" adopted by his Brigade... a flesh wound was worth 2 points, a severe maiming 5 points, killing a Queen's Beret soldier was worth 10 points and personally hacking his cod-piece to bits with a saber garnered 25 points.
Due to almost 40% of the Queen's Beret Brigade being killed by friendly fire and the other 60% being mowed down by the Confederates, the entire Brigade was removed from the rolls by late 1863, and condemned to a minor footnote in history.
So, I reckon you were right. Actually, I'm kind of glad YOU found it.
The really good news is that 145 years ago, some local boy likely scored 25 points off your find.
Dig-it!