The Kastrup Glass Company [1847-1965] and the Holmegaard Glass Company [1825-1965] produced many Art Glass items over the years. In 1965 they merged into the "Kastrup-Holmeguaard Glass Company" Both named after there respective towns in Denmark. I found this "paper weight" in the attic. It is a full 1 3/8" thick and 3" across. Very heavy. I can't find any reference to either of them making any insulators but if they did, they would be beautiful.

Enjoy

Dan Gay