On the left is a purple "diamond" (unembossed two-piece transposition top (in lighter purple) compared to what is believed to be a CD 191 made by one of the Denver glass insulator companies (on the right). As you can see there are molding differences. You Denver and Canadian glass guru's likely can tell more differences in a heartbeat! These photos are provided by me for comparison (only) and for further education that may evolve from these depictions. Thank you.