Bankers Lamp with Emeralite Cone Shaped Shade, Goose Necked.

The shade is a deep green glass (Emeralite?). The lamp is heavy, I think it may be brass. Underneath there is a circular disk that appears to be cast iron or a stone of some sort. I can't find any markings on it and am curious as to what the name of it is or what it may be worth.
I have searched online and can't find a pic of this style anywhere! Thanks!