Yike! I just realized I used "opalescent" the wrong way. I should have just said opaline. I asked about it, because one import company, JI Co, had pheasants that looked opalino, but they achieved it in a different way than Toso or Seguso. The company that made glass for JI Co had an opaline sommerso vessel -- the core -- that was white. Then they would put some color into the glass right around the core. It had the effect of making the whole animal look opaline. I guess one could say it was a poor man's opalino. The glass looks opaline in pictures, but one can tell when it is in hand. This is why I asked. If the glass is colored opaline (color and opaline together), the it is probably a higher quality piece.
Archimede & Co. did such a huge range of pieces, it is difficult to see them all in a lifetime. It should be an interesting hunt. I just remembered the link you gave, so I'll have to check.