Found this in an antique/junk/hoarder's shop south of Youngstown Ohio. Pretty glaze, and a Thomas mark I'm not familiar with.

Connor Stoehr gave me some background about this piece: "This is very late production Thomas with the Delta Star sandblast marking. In 1957, the Thomas company was sold to the H K Porter, which merged it with their Delta Star Electric division and sold insulators under that name. This continued until 1963 when the Thomas plant was closed for good."