I have looked at this image in the Caithness Collectors Book (2nd Edition) pp51 many times and it doesn't seem to conform to my Fireball paperweight. Excellent book and most likely I have it wrong or angle of picture is misleading.
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Listed as CT305 Fireball 1983 by Colin Terris - book image is ball with flame of glass - mine is central envelope of glass in red/pink glass.
Maybe there is some give and take re production.
Thanks Adam