Mithril armor is a type of light armor. When you reach level ten you can get a set for yourself. This is the highest class of light armor that shops will normally sell.
For the most part, it seems to be of a higher quality of Chainmail armor.
|Armor Piece||Base Value||Weight||Max. Armor|
Notes: "Base Value" refers to the actual value without mercantile or disposition affecting it. "Max. Armor" refers to the maximum amount of armor the piece can provide, assuming maximum stats and skill.