Topic: White and ruby cased napkin ring

[flying free]

Thanks.  It's an interesting comment in Scientific American and it's exercising my brain.  I wish I was a chemist and understood this more.
Does it mean that if red glass is lead glass that the red is gold ruby glass rather than copper ruby?

Or could it mean that if it's red lead glass it could have been made with selenium? see here:
Source- Journal of the American Ceramic Society, Production of Selenium Red Glass, F. A.Kirkpatrick and George G. Roberts, First published Nov 1919:

https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/j.1151-2916.1919.tb18751.x#:~:text=The%20production%20of%20red%20glass,selenium%20glass%20of%20satisfactory%20quality.

Or is it possible that the red colour was bought in in blocks/sticks/cakes readymade  for melting and used for casing? i.e. not made in house.
If they were copper ruby blocks then I have a question - is it possible to case lead glass with non-lead copper ruby blocks (me assuming they are non lead blocks/sticks because of the article quoted)
Otherwise are the blocks/sticks gold-ruby glass bought in ready-made to case these lead glass napkin rings?
Or is it possible the maker was making their own gold-ruby glass to case the napkin rings? 

From what I read the process of making both gold-ruby and copper ruby glass is difficult.