Large Stiffel Hanging Ceiling Lamp?

Large Stiffel Hanging Ceiling Lamp with brass chain , Thats is guessing from the similar ones I have seen...? Everything is original on it, no scratches or nicks .. just dusty. The base is yellow, it takes 2 bulbs, the shade is original so not sure the correct color it should be, it's a yellowish color. I know sometimes color fades but i haven't noticed if so. It isn't one of those that has a string pull, it has a button switch for on and off. I have been researching a few things past few days and I can not find one of these anywhere on the Internet! And I know this is not one of a kind. So beings I haven't been able to find one, I cant give it a proper name and description. Would love to know the year, if its porcelain or ceramic. Any ideas?