Where are the diamonds (citadels)

I currently have 4 days in mapping I'm level 92 and still have not seen a CITADEL anywhere on my atlas. I know it may seem a bit unreasonable on my behalf to expect to.see one or more with in only 4 days of solo mapping but wtaf GGG WHERE ARE THEY. This has happened to me personally the last 3 leagues. New Zealand EXPLAIN