An important key for correctly identifying it is, what metal is it made of... which unfortunately you did not say anything about in your description of this mystery-object.
It doesn't appear to be made of iron. In your first photo, it seems to show the corrosion/patina characteristics of either pure Zinc, or a high-zinc-content White Metal alloy, such as Pot Metal. If that guess is correct, the object is from sometime in the 20th-Century.