Luckily, I found it last week as part of the Illamasqua summer sale, and was quick to pick up a bottle online. It's a grey-blue shade, a bit reminiscent of Eyeko's similarly-themed Rain, although this is a jelly rather than a creme, and is made more unique by the inclusion of small silver flakes of reflective stuff that give it a really striking twist.
This is 4 coats (jelly polish, go figure). The flakes are very densely packed, however, so it could easily be worn as a topcoat over a similar colour to get the same effect more easily.
Raindrops is currently £5 in the Illamasqua summer sale. Regular polish price is £13.50.