Hey, maybe I'm wrong but I always thought "artificial" was referring to a harmonic played on a fretted string and natural's are played on open strings. I understood that pinch harmonics can be either natural or artificial. I guess there isn't really a standard authority for all these terms though. Life's confusing.
By the way, respect! How'd you get diagrams into postings Azrael? Respect Also for that list of intervals, fancy knowing that!