Nails Inc Porchester Square and OPI Rainbow Connection.
The base colour looks a bit more green toned in the picture, but it is grey, which leans beige/brown. I had it on my nails for a day, then added Rainbow Connection to it, and topped it with Seche Vite. There are endless combinations with this popular glitter polish. Still want to try Models Own Utopia, a dusty pale pink, and black with it. You can see that my nails all have a different amount of Rainbow Connection on. It can be built up for a huge glitter explosion or just lightly for a hint of detail. Either way it's so colourful and eye catching, and I understand why it's so popular and a total sell-out.
If you can't get your hands on Rainbow Connection, try Nicole by OPI's Rainbow in the S-Kylie, part of the Kardashian collection, which is an exact dupe. You can get it on ASOS or Lena White, a UK official OPI stockist.