When I photographed that item in 2003, along with the majority of the Perth Museum weights, my catalogue notes referred to it as a "Cut and faceted dome" rather than a paperweight.
Perhaps I simply linked it with the other Stuart Crystal item in the collection - which I called a "Triangular column", but which the SCRAN details list as "... prism paperweight". But maybe I was also refusing to admit that these were paperweights because of the decision in 1980 to abandon paperweight making (in its usual forms) even in the light of the many new ideas being generated by the workers at the time.
Anyway, whatever my reasons were, I had forgotten all about these items until now!