[Wrana]

1. Probably no - there is no actual "magical" quality for armor, as it is for weapons. Magical items which are armor get most of their qualities from being magic items, not as armor stats. Modding manual lists what stats you can actually include for armor - they are also ones any unit with this armor gets. This also means that if you want a unit you mod to have, say, Fire Resistance from Fire Plate, you must both give it Fire Plate AND write Fire Resistance among its stats...
2. According to Database, it gives 20 armor-negating damage.