Board Thread:Administrator's Noticeboard/@comment-1250011-20131107193327/@comment-17754049-20131111163344

Basically,

Quality =/= Rarity, neccesarily. There can be common high quality items and rare high quality items. The colors only represent how cool/potent an item is, not how difficult it was to attain it.

A Sniper Rifle is Quality, but telatively easy to get.

An Uzi is Rare as all hell, 1/50k drop chance, or the Rune Wizard outfit, with a very small spawn chance for the creature to spawn.

Something you don't often see, and is difficult to accuire, is rare. Late in the game, you can get all kinds of high quality items, like temple keys. With the right weapons, Plantera is nothing, and he drops jungle keys and high quality gear all the time.