Arts and Crafts glass light shades: slag glass?
I intend to sell these but I don't know what to call them. I want to make sure I use the right keyword(s) in the ad so they can be found if someone is looking for something specific. What is the proper name for this type of glass? I keep thinking of slag glass, but I don't think that's correct. It's quite thick, marbled and has a pebbly texture on the outside.
The inside is smooth: