Sigma Nu Pin?
 

I was going through my late grandfather's personal items, and I found what I think is a Sigma Nu lapel pin of some sort, but it's not the regular initiate pin, nor the pledge pin. I was hoping someone could identify it for me. Is it an official pin at all? Some kind of recognition pin maybe? It's about half an inch wide and it looks like this:
https://www.hjgreek.com/assets/image...large/9839.jpg

Or maybe it belonged to my grandmother, I suppose--a sweetheart pin maybe? She was a Pi Phi (like me!)

It's just a lapel pin. There's nothing official about it except that those are definitely our letters.