After embroidering the mingles sample I showed yesterday, I thought 'why not see what happens when you bead with metallic threads such as DMC jewel effects and precious metal effects'? They would add not just colour, but also shine, wouldn't they?
First I tried purple metallic thread (E3837). Pulled the 6-ply thread through doubled so it's 12 strands filling the holes of the smoky amethyst beads. It looks similar to a metal lining (like silver-lined) or sparkling colour lining (because of the added colour). Don't think it added that much: you could get something similar by buying lined seed beads to begin with. Probably cheaper and easier than handling delicate metallic threads. But if you have a mix of thread and beads that you like, it could be fun to use.
I didn't give up though, thinking I wanted something more out of it. And the answer was: using blended threads or ombré/space-dyed/multicoloured thread would give a variegated metallic effect most likely possible to acheive in a bead factory by lining the beads.
There are multicoloured metallic threads, but I didn't have any. Instead I blended two shades, a jewel effects blue and a precious metal effects in silver (E168). Lost the label for the blue thread and there are several metallic blue shades so no colour number for that one (might be E825). The result is similar to the one you could see in the mingle sample, but with some added metallic shine. Again, smokey amethyst might not have been the best colour to show off these threads, but I used what I had nearby and what was transparent enough to show the colour effect.
I do have some metallic rayon chainette and other thicker threads/cords with some metallic threads woven into them, most of them space-dyed. Not so useful in embroidery -- unless I couch them, I suddenly realise -- but could be used for some fun bead crochet or stringing/knotting.