Featured My First Slag Glass Lamp

I've never really been interested in things like this but I was at an estate sale and came across this slag lamp. My question is how do you date it without a maker. I cant find a mark anywhere. I believe the cord and harp were replaced at some point (unless this is a repro and im just missing it)

 

it won't be your last...

 

Maybe. It's just that this is really the only pattern of slag lamp I've ever really liked.

 

On the electrical plug, are the prongs the newer two size? or older both prongs same size?

Found one that sold on ebay 9/30/18 $225
Also found one in blue slag and another in green slag.

 

You'll be able to tell a lot from the socket switch. . . if original, one can date a lamp to the decade it was made, or even 5 a year time period. I collect pre 1920's lamps, it's amazing how well the sockets were made in the early 20th century - I see many with factory sockets that work perfectly.

 

Can't really tell, but am betting the cord is a replacement.......BUT, I absolutely LOVE the lamp!!!!!!!!!!!