Earth armor spell

This spell increases your armor by x amount but it doesn't say physical, does it work against elemental too?

Yes it works against elemental. The only time armor doesnt work against everything is if it says it specifically works for something. So, if you had an armor piece with 30 armor +15 to fire damage, it would be 45 armor vs only fire damage. If you had a piece of armor with 45 armor and no bonuses, you would still have 45 armor vs fire (and every thing else). Hope this helps.