One hard to find, Pale Lavender in color, glass door knob. Unfortunately this one is in rough condition with numerous chips and scratches and an enlarged threaded shaft (probably from insertion of a bolt for use as a stationary door pull instead of for use with a mortise lock.) Also, it has a slight move (click) in the brass shank, no set screw with stripped threads in that bore as well.
Just plain rough…but authentically old!
Diameter (Flat to Flat): 2-1/8”
Diameter (Point to Point): 2-1/4”
Shank Diameter (rides in the doorplate collar): 11/16”