3 1/4" tall at the highest point and 3" on the outside diameter. Round-footed. This piece is considered rare.
Jim Retzloff received a copy of pages 18 and 19 of Hocking's Catalog C from Phil Hopper. These pages are headed:
"Queen Mary" (page 18) Prismatic Crystal (page 19)
It appears that Queen Mary was the name of the pattern and prismatic crystal was a description of the type of pattern. There was no mention of a "Prismatic Line."
