I'm losing track of what I've blogged and what I haven't. I've been so crazy busy that - well - somethings are starting to get away from me.
This is Double Helix 507 Speckled Opaque, reduced and encased. I suspect that any of the dark high-silver colours that appear black(ish) and reduce to a metallic sheen will work the same way, e.g. Triton.
Let it cool, and very gently reduce it - bringing it just into the bottom edge of the flame. Reduce it until you see a metallic sheen - it doesn't take long. If you get the subtle metallic purple/green look - you will get the nicest results.
Then encase it without reheating it or letting the flame touch it before covering it with clear. This means you have to heat the clear up and have it ready to go and encase the whole bead in one swell foop. Occasional a bead will be so cool that when you put the clear on it, it cracks. So long as it doesn't fall off - keep going. After encasing, you can heat the whole thing up and re-heal it.
As you can see - it took a lot of experimenting to get the steps nailed down. Reducing once cool is really key to keeping the blues and avoiding the greens and ambers.