Glass doorhandles are rare today, in part because of the liability risk of people being cut by broken glass. Most glass doorknobs are molded or pressed and were particularly popular about 1900. Doorknobs made like paperweights are interesting (OGP P.42) When I attempted to track down a source for brass fittings to hold the glass, I found they were somewhere in India, where the doorhandle units came from.

a knob used to release the catch when opening a door (often called `doorhandle' in Great Britain)

A doorhandle is the device mounted on the exterior and interior of a door for the purpose of opening it.