The secret to these fabulous beads is twofold: First, you need frit. Second, you need silver leaf or silver foil.
These beads are made with "House of Blues" frit from Val Cox. Val changes frits regularly on her site, and as of this writing, the House of Blues mix was not available, but keep checking if you like it...it may return!
Frit, quite simply, is ground up glass. You'll see things marked as "reduction" frits, which means that they change color when put into a propane-rich ("reducing") flame. Reduction frits are always 96 COE. You can use a small amount of 96COE glass on the outside of Moretti/Effetre (104 COE) or Bullseye (90 COE) glass, but you should never encase it unless you are using 96 COE glass. There are comparatively few colors of 96 COE rods and stringers, but if you can get used to using fusing glass and cutting it into strips to use for lampwork, you'll have a pretty much endless palette.
To start, lay out a small pile of frit on a marver surface, and put a a small strip of silver foil to the side where you can access it easily. (If your frit is ground small or powdery, be sure to wear a dust mask when you're using it--enamels and powdery frits will get into your lungs.)
To make these beads, make a small barrel of transparent violet glass, then heat it and roll it in the frit. Melt the frit in and roll the bead on a marver again into a smooth barrel.
Place the foil strip on the marver, heat the bead, and roll it up in the foil. (Whenever you use silver foil in beads, you must be sure that you have ample and not just adequate ventilation, since the fumes from the silver are even more toxic than those from the glass alone!) Heat the bead again until the silver balls up.
Keep the bead warm, but let it cool down slightly so that you aren't going to smear the underlying glass, then encase it. These particular beads are encased in a color called "neon orchid", which is a color-change glass. It looks light purple in some lights, light blue in others.
Pop it in your kiln, and make some more!
Here's the really cool thing about adding silver to glass:
Glass colors are not created with dye. They're created, in many cases, by adding various minerals to the silica. Thus you get colors like "Rubino Oro" (fuchsia pink) by adding gold. Silver, naturally, changes this composition somewhat. When you coat Rubino Oro with silver, it turns to a very gold color, which I can only assume is because the silver draws the gold out of the glass. If you look at the picture of these blue beads closely, you'll see that each little silver dot is surrounded by a ring of gold. I assume this ring is from the purple base and the purple casing since both of those must also have some amount of gold. True blue glasses don't get this effect, as you can see here:

And the neat thing about frit is that you get a different reaction between the silver and each color of frit you use, so you can get really wild variations. Experiment!