The icon colors aren't really "rarity" colors anyways. They reflect what type of gear it is. Grey is normal vendor gear and also covers any kind of regular item, mat, etc. Pink is aetherial gear. Green is for 4-man dungeon gear, GC gear, or crafted gear above ilevel 50. Blue covers endgame-oriented token gear, 8-man dungeon gear, and most achievement/quest gear. Purple is relic weapons. There are always a few exceptions here and there for various reasons, but these rules hold true in general.