| The Gorgon |
I came to this thread with the assumption that the Mage Armor spell does not create armor. After reading this thread, I am 100% certain that I was wrong. I was swayed by two factors: one that was repeatedly pointed out in this thread and another that was never explicitly stated.
1. Implication: As Remy astutely pointed out, the Mage Armor spell description strongly implies that mage armor is armor by contrasting it with mundane armor. A careful wording of the spell would have instead contrasted the Mage Armor effect with 'actual' (rather than 'mundane') armor.
2. Explication: The spell description explicitly refers to the Mage Armor effect as mage armor (e.g., "Since mage armor is made of force'). Note that there is an important distinction between the spell name and the spell effect. As Malachi accurately pointed out, "The spell name has no mechanical function." If the spell was named "4th Level Spell", that would not make it a 4th level spell. However, the spell description clearly refers to the effect of the Mage Armor spell as "mage armor". Note the lack of capitalization of "mage armor" - it is not being used as a name (a proper noun), it is a description. So, the spell description explicitly tells us that the Mage Armor force field is armor. Now, the fact that it is armor does not mean it is the same kind of armor as other armors. A toilet bowl is a very different kind of bowl than a cereal bowl. But both are unquestionably bowls.
It may be worth adding that "armor" is not a game-specific term (like "hit points" or "saving throws"). I am aware of no rule that says, 'for game-purposes the only things that count as "armor" are these X things'. Without such a rule, we have to rely on the rules of English to determine what is and is not armor. So, if the spell description says that it creates red armor, blue armor, cold armor, hot armor, steel armor, wind armor, mundane armor, or mage armor - then the rules of English tell us that the spell's effect is, in fact, armor.
And yes, this argument also reveals that natural armor is armor.
The real problem is with the Magical Vestment spell description. If it was not intended to work on mage armor, it should have specified mundane or enchanted armor, shield, or clothing as valid targets. By simply identifying "armor or shield" as a the spell target, that includes all armors, including mage armor (and natural armor). I admit, the "suit of armor" part of the spell description does give me pause. There is no basis for claiming that mage armor is a suit of armor. But there is also no basis (that I'm aware of) for saying that a chain shirt is a suit of armor. And the fact that an outfit of clothing counts as armor (and not a "suit of armor") for the purpose of this spell, I think the "suit" descriptor just has to be ignored.