What a pleasure to discuss glass with such a learned group!
"I have to admit, much to my shame, that my knowledge in this area is woefully inadequate, particularly for one who attempts to explain to others how glass was made. Perhaps my enthusiasm masks my lack of knowledge. "
I hope that's no reason to be ashamed - sounds like me!
I'm not very knowledgeable about molds, for I'll take a stab at the mold ring question - pure conjecture, understand, but I like that kind of thing sometimes, even when my hypotheses are wrong. I'd guess it's a part of a mold that fits on top of two or more other parts that form the sides of the mold. It would be donut-shaped, and the plunger would come down through the middle. In this case it would bear the negative of the inner half of the handles. This would address my earlier uneasiness about the idea of having a patterned plunger. ...Now to wait and see where I'm wrong!
I'd never heard of a spring punty, but snaps or snap cases are sort of like tongs, with curved ends designed to hold a piece of glass.
Unless the leaf is glued on (highly unlikely), it couldn't have been applied by another maker. Well, it may not be physically impossible, but it would involve very slow reheating to a temperature at which it was hot enough to fuse with the leaf, and the two formulas would have to have compatible coefficients of expansion.
Having said that, I'm hoping I'm wrong. I used to have a flower frog that I strongly believed was made of a piece of glass that had glass ropes added to it at a later date.
"The pinkish colour is merely the reflected 'visible' radiation from the UV source. With a fine spectrum UV source (with no visible light) only fluorescence would be seen - the rest would be black. Lamps are available in the reprographics world but are lethal to the eyes."
This may be the case with this basket, or opalescent glass in general, but it is not always so. I've seen modern colorless glass fluoresce a pinkish color of a different hue from the UV lamp I was using, and have enough experience with using the lamp to usually know when something is fluorescing or reflecting. Mr. Vaselineglass's spectroscopic examples were all uranium-doped, but there are other minerals used in glassmaking that fluoresce or enable fluorescence in longwave UV light (manganese, for instance). Martin's very interesting comments about neodymium absorption spectra in different lights are about a different phenomenon. Fluorescence is when light (or chemical) energy results in the excitation of molecules, which then give off light of a longer wavelength.
Phew, sorry about the long post! I love these subjects.
Oh, forgot to answer this: "BTW â€” Apologies, I had to ask â€” Are you a descendant of the Silber of Silber & Fleming, whose c.1890 mail order glass and china catalogue is so useful to us today?"
No, sorry, never heard of 'em! Is this a common reference on your side of the pond?