Copper ruby

[Steven O'Day]

Ran across this patent, they add a small amount of bismuth oxide to the formula. Anyone try this?

Manufacture of ruby glass

[Pete VanderLaan]

It's curious. Bismuth is really a heavy metal right there with lead. It also uses cyanide. It also wants to use stannic, not stannous oxide which is an opacifier and not a reducing agent.

Honestly, I think black tin will yield better results. Bismuth also is not cheap. If anyone tries it, let us know.

[Jordan Kube]

The boro melters use it, I think. There's some stuff to learn from what they are doing.

[Pete VanderLaan]

I think it's the zircon. Cyanide? no..

[Bradley Howes]

Originally Posted by Pete VanderLaan

It's curious. Bismuth is really a heavy metal right there with lead. It also uses cyanide. It also wants to use stannic, not stannous oxide which is an opacifier and not a reducing agent.

Honestly, I think black tin will yield better results. Bismuth also is not cheap. If anyone tries it, let us know.

This is now definitely on my to do list once I get back to Alfred and can do my GAE work again. My experience with bismuth thus far has been in calcedony. I was taking inspiration from Antonio Neri from ~1660 AD. He used mercury in his calcedony melts. Bismuth and mercury are part of a family defined by Volf that goes to the tune of Hg-Tl-Pb-Bi (80-83 on the periodic table). I made my own bismuth oxide from bismuth metal by reacting it with nitric acid and reducing it to oxide with sodium hydroxide. The amounts I was using though was over the .31 wt.% limit specified in the patent that produces browns and blacks from the formation of bismuth metal particles. (Side note: I once saw a wonderful honey amber orange brown color made from bismuth by one of the Alfred undergrad engineering seniors.) It might be worth revisiting that avenue.

I’m very suspicious of the cyanide. I’ve never used it and I have no idea if it volatilizes from the melt somehow. I also have no idea what role the cyanide plays in the glass. Is it some kind of reducing agent?

[Pete VanderLaan]

well, pick your poison, cyanide or mercury. the presence of arsenic in glass will certainly knock you on your can. Volf declares that Mercury has no role in glass on the one hand and in the other refers to distinct color changes in batches where it's present. I have had it suggested to me that bismuth could replace lead in whole or in part but at that time the price of bismuth was over eight times the price of lead.
Bismuth is certainly used mixed with silver salts to help keep them from oxidizing away as a surface treatment but conditionally in its nitrate form.

I think pursuit of the Neri observations regarding mercury are worth pursuit. Dino Rosin gets really wild chalcedonia effects and he doesn't talk much about his formulations.

[Bradley Howes]

Just by pure chance, I was looking at the index of Weyl for aventurine, I saw a note for Bismuth Oxide, in Ruby Glass pg.343. It wasn't much but Weyl stated lead, bismuth, and tin are all metallophilic, with tin being the most effective (hence its use in ruby glasses). Again, it wasn't much, just another piece in the puzzle.