Serene is one of three polishes from Avon's limited edition Spring collection, Zenergy. I purchased my bottle for $3.49 when it first appeared in the campaign books, but it will be $6.99.
I was a little disappointed when this polish arrived.. In the campaign book it looked much darker and more turquoise-y. It's actually much lighter and more like a baby blue or robins egg blue with almost a hint of mint, too. Oh, how I dislike inaccurate product photos.. :(
Here it is on my nails using two coats. You can get it pretty much opaque with just one coat, but I used two for good measure. The formula was okay, and it dried quite quickly without me having to use a coat of Seche Vite. I did get some tiny bumps (or bubbling) on my thumbs, but all the other nails were fine.
Serene is a pretty color, just not what I was expecting. It's also not the most unique color, either.. If you like these kinds of shades you probably have something very close to it already. I'm not that big on light blues personally so I only had one similar polish which is China Glaze's For Audrey:
I thought they might be dupes until I swatched them side by side. Serene is on the left and For Audrey is on the right. Serene is lighter, and like I said, has a very slight hint of mint to it. So, they're quite similar, just not dupes.