I've totally fallen in love with this polish! For The Twill Of It is part of Essie's A/W 13 collection. I'd describe it as a metallic dark grey with purple and green duochromes. It's one of those polishes that people notice, and someone at work called it the most beautiful colour she's ever seen! It's also one of those polishes that I sit and look at on my nails.
My photos don't really do it justice, they don't capture the gorgeous duochrome in anything like enough detail, but here's my attempt anyway:
I wouldn't say it's a unique colour - plenty of nail polishes have been out in recent times with a duochrome to them, some which are pretty similar to this - but I do think it's absolutely gorgeous. Application is easy and wear time is ok for a metallic polish. Really glad I bought this polish, definitely my favourite from Essie's latest collection.