OPI... Eurso Euro is a polish from OPI (which you probably could've guessed!) and is from their Euro Centrale collection. It's described simply as a 'deep blue cream', but I see it as a 'blurple'!
I don't think this photo is the most accurate (and I apologize!) - it was taken with flash in the sunlight. In person this shade is definitely darker and you can notice the purple-ness in it easier. I suggest looking up some different swatches of it to get a good idea of what it looks like!
Here's another picture that's a little more accurate, and was taken without flash. I find it's still a bit darker then this but it's the best that I could get. Alright, moving on..!
You'll need two coats of this polish, but it's easy to work with. The first coat is thin and a little streaky but with the second coat everything will be fine and dandy! I really like this color and I'm happy to report that I don't have anything like it!