Iridescence

Carnival Glass was often iridised using ferric (iron) chloride sprayed onto the hot glass. This gave an orange marigold colouring. Stannous (tin) chloride was also used (and still is the iridescent spray of choice for iridising glass, for example by Isle of Wight Glass studio).

Larry Freeman reported (see below for references) that "the burnished gold Aurene color came from the use of tin chloride. The addition of iron chloride deepened this gold to a reddish tint". Chloride of antimony applied on top of iron chloride is supposed to have produced blue colouring.

When Webb & Sons, in the UK, made their iridised Bronze Glass (1878 onwards) their application for patent stated that: "the glass articles are exposed, while in the nearly molten state after blowing, and before annealing, to the fumes generated by placing chloride of tin, alone or mixed with the nitrates of barium and strontium, upon a hot plate or spoon. During this process the articles are placed in a muffle or chamber into which the fumes are introduced".

References:

Larry Freeman "Iridescent Glass"
Charles Hajdamach "British Glass 1899-1914"
Heacock, Measell, Wiggins "Harry Northwood The Wheeling Years"