Blue Luxin, or Frostglass, is a brittle substance. When drafted well is smooth and can be very sharp, making for excellent weaponry or projectiles. Even when poorly drafted it is a more than suitable armament, although it will have a tendency to flake apart, leaving chalky residue all around.
Blue is associated with the sin of Envy and the Old God Mot. The corresponding virtue that Blues are to aspire to to prevent this sin is Kindness.