I picked this insulator up recently only because of the glass on dot on the dome. The glass dot is very much centered and uniform, and is supposed to be there. The embossing seems to be the prismic embossing and has the sharp drips. It also has some milk swirls in the glass and one swath takes about half of the dome reveal (Display Visual). I am not looking for value or rarity, just wanted to share an interesting find I had not yet encountered since I started collecting insulators. Enjoy the photo example and thank for letting me post to the forum,

Bill Vincent