The one exception to the rule that requirements are not abilities. Prowess, Wizardry, and such are not abilities in the fullest sense of the word; they are triggers for disparate abilities, obstacles to be overcome before the activation of one of the hodgepodge of abilities under that one umbrella, is allowed. Activated gems are such an obstacle, but at least they are interactive in a fun way, so an exception. Normally we will list them as Category:Triggered abilities, but Activated gems can be a subcategory of that.