Welcome to the forum. Happy Zed hunting. The Azure is rather a gorgeous colour. It's actually not that rare as such in the numbers that they were produced. Some countries seem to receive more colour allocation than others.
Rare would be limited run colours such as; Solar Orange 2007, San Marino Blue 2007, Brick Yard 2003, Interlargos Fire 2006, Ultra Yellow 2005, oh and one of the silver tones. (Lol, yes I know I've used the American/Auz/NZ names ).