An odd-shaped ring, cant ID
 

Hi everyone, jewelry newbie here..I have this odd-shaped ring that I
cant quite identify. Its pretty much square, but with slightly rounded
corners. IOW a near-perfect square. There's no stone or marks on it, jut
a plain square band. I don't remember where I got it, but I've had it
for several years. I cant wear a round-band ring, due to a slightly
swollen joint on the finger, so this ring is all I can wear. I'd like to
find something similar, but I don't know what to search for. It was
once pretty shiny, but over the years, its oxidized a little, and shows
a tiny bit of a coppery sheen where it contacts the hand.

My question: Is this a real ring or is it hardware? I've thought about
it a lot over the years, and have done several searches online, but
nada.