If you are looking for a dark purple nail polish during the autumn, you can stop looking now, Yves Rochers Nagellack in the shade 102.Aubergine is a super nice, dark, aubergine purple varnish that is comprehensive even after one coat. Absolutely wonderful!
I have that nail polish on one hand right now, but I have a hard time with completely dark nails on myself, so on the other hand I have a lavender purple, shimmery nail polish from China Glaze Nail Lacquer in the shade Astro-Hot. Both paints are great together I think:)

Or what do you say? Fint va?
(I am aware that my nails are a bit dented and uneven, hehe. I have to file them a bit more properly!)
 Hugs are!