What is this possible old coin found in Western Ukraine?

I think, at early eighties, when I was a child, I found this “coin” in my room, at the second floor of a standard Soviet building in Lviv, a city at the west of Ukraine. The house was build, as far as I know, in 1963.

Images in a resolution 600 DPI are here and here.

The diameter is 2 cm.

I don’t know what is it and how it occurred in my room.

I have not seen any symbol or emblem strongly resembling that on the “coin” on other coins or medals before or later, so I do not offer anything to compare this to.

But I wish to identify this historical thing, before I shall pass into history myself.