Pittsburgh Plate Glass Mirror

I found this mirror at a second-hand store.  Including frame, it measures approximately 15 1/2" by 23 1/2".  On the back is a stamp that reads "P.P.G. Co.,  Ford City (??)  June 1, 1920 (??)" and has the image of an eagle over branches.  The glass has a beveled edge.  The coating on the glass has a lot of crazing, visible from the front, but it's 99% intact.  The frame is solid wood and appears to be of the same age as the mirror.  I don't have any other information as I bought this second-hand.  I'm hoping someone can help me to learn a little more about my find!

Fair