purchased by me
That blue is matched only by Sinful Colors Sail La Vie, originally a limited edition color in its namesake 2013 collection. It's available now where Sinful Colors polishes are sold, but I don't know if it's still LE or now part of the core collection. The formula is surprisingly unfussy for such a pastel color--opaque in two coats, self-leveling, quick to dry, quite shiny and with nice viscosity.
I'll be wearing this frequently, especially next winter when I'm desperate for blue skies! Sail La Vie can be found right now at drugstores, in either the Bloomblast counter display or in the Color is the New Black corner end cap.