Nessie Ice it's called - and the rods vary, some look black, some are a dark blue/green.
It is a very dark colour, too dark to use by itself, see spacer on far left. Laying over white reveals it's true nature, green with tendrils of blue, like swimming through an underwater weed bed - which is a very bizarre sensation, btw, if you haven't tried it. The soft touches of the weeds are almost reassuring, like they are holding you up, but in the back of your mind is every horror movie you've seen where the diver gets snagged and pulled to the bottom to be eaten by a giant mutant tentacled creature.
But I diverge. ;-)
The larger bead is a clear core, Nessie Ice, encased in clear, and mashed. This shows it's streaky nature well, and the bubbles, a result of my hasty casing, enhance the effect. A few fish murrine on top, and you'd be good to go!