I have several glasses and the item pictured from my great-grandmother. It was always referred to as Swedish Milk Glass by the family. It was always kept separate from the other crystal as it was supposedly diseased. Supposedly, the opalescence could be spread to other crystal. (family tales are interesting)

It looks like on the bottom of the rondel that there is some kind of mark – I’m not sure if it is a punty mark or letters. It is very hard to tell.

If anyone has any ideas what this glass is, I would be very greatful.