The lamp is 2.12" (54mm) at the widest diameter and the overall length is about 4" (102mm). The material around the base looks like plaster, with small metal fingers embedded into the plaster. Long wires exit the plaster base for the electrical connection. The filament is rather thick looking and has a very dark appearance. There is a very small square label still affixed to the glass which seems to only have a letter "C" or "G" in the center of the label in red print. This may hold the best clue in identifying this lamp?