This smooth, deep blue crystal is warm to the touch.

A crystal of screening enhances a suit of armor with force, enabling it to protect you against the attacks of incorporeal foes.
This augment crystal imposes a –5 penalty on touch attacks made against you by incorporeal creatures.

Prerequisites: Craft Magic Arms and Armor, mage armor.
Cost to Create: 500 gp, 40 XP, 1 day.