Two coats; direct sunlight. 

Playing around in the nail bar in Sephora led to wandering the sections of one of my two favourite brands - YSL (the other being Dior). A short wander later and I came across the polish that stole my heart, Bleu Cobalt. 

Bleu Cobalt, in the bottle, is an ever-so-slightly shimmery navy with purple reflex. On the nails however, I love it even more. The purple is non-existent - which is good for me as I'm not a fan of purple polish - and the shimmer is so fine that instead of looking like chunks of glitter, reflects light in a heavenly way. The cherry on top was the most beautiful brush I have ever used - flat but not too thick, allowing neat and easy application in a quick two or three swipes. Three days later, and still not a single chip. I went through a slump and didn't wear nail polish for a whole month because I was tired of the mundane and overused colours I was spotting, but YSL's Bleu Cobalt has captured my heart, sitting itself as my (one and only) favourite polish.