Nancy, there are different ways of doing it and most of them involve either silver (or fuming with silver) or reduction frit of one kind or another. Some frits work really well for this, and one of them is iris gold...
These beads were made by pulling a stringer of Moretti light brown transparent glass that had been rolled in iris gold frit. I laid the stringer on (all squiggly) different bases-- carnelian works really well, and then encased that with clear or pale transparent lavender glass. There is no blue glass in these beads... all that blue comes from light brown glass and iris gold that's been encased.
Andrea Guarino-Slemmons is a master at making moretti look like boro and teaches a class about it!
lynne
