Guild Wars 2

You can buy Sun Beads any time and there are common materials that are harder to get, so why are they considered a rare crafting material?

Probably because the items you make with them are rare quality?

They’ll actually become unavailable in certain circumstances, although the event chain to clear the vendor is both short and fairly easy. On the other hand, you can buy complete rare weapons from city vendors for relatively small amounts of Karma. The grades have to do with item quality, rather than what you have to do to earn something.

Practically speaking, they also don’t follow the use tendencies of any of the fine crafting ingredients, and were probably labeled as rare to help make clear their utility before the bank could store non-fine and non-gem crafting ingredients.

That said, it is kinda goofy to have weapon recipes that require 75 of the things, and then only sell them one at a time. ((And Beaded Hylek Necklace should probably require more and be a rare grade item, as well.))