Armor Augment Crystals

Here follows a table of all armor and shield augment crystals in D&D 3.5. All least armor or shield crystals will attach to any masterwork crafted armor or shield; lesser crystals can be used on any armor or shield enchanted to at least +1; greater crystals can be used on any armor or shield enchanted to +3. Armor and shield property bonuses are ignored when considering the enhancement bonus for purposes of what grade of crystal can be used with them; only enhancement bonuses that add to AC count.

Armor and Shield Crystals
Crystal NameCrystal SlotBase Price by Crystal Rank (Item Level)
LeastLesserGreater
Clasp of Energy ProtectionShield500 gp (3rd)1,500 gp (5th)3,000 gp (7th)
Crystal of Adamant ArmorArmor/Shield300 gp (2nd)1,400 gp (5th)3,400 gp (8th)
Crystal of AdaptationArmor500 gp (3rd)1,500 gp (5th)3,000 gp (7th)
Crystal of Aquatic ActionArmor250 gp (2nd)1,000 gp (4th)3,000 gp (7th)
Crystal of Arrow DeflectionShield500 gp (3rd)2,500 gp (7th)5,000 gp (9th)
Crystal of Bent SightShield500 gp (3rd)
Crystal of Glancing BlowsArmor500 gp (3rd)3,000 gp (7th)5,000 gp (9th)
Crystal of LifekeepingArmor200 gp (2nd)1,000 gp (4th)5,000 gp (9th)
Crystal of Mind CloakingArmor500 gp (3rd)4,000 gp (8th)10,000 gp (12th)
Crystal of ScreeningArmor400 gp (2nd)1,000 gp (4th)3,000 gp (7th)
Crystal of StaminaArmor300 gp (2nd)900 gp (4th)2,700 gp (7th)
Iron Ward DiamondArmor500 gp (3rd)2,000 gp (6th)8,000 gp (11th)
Restful CrystalArmor500 gp (3rd)
Rubicund FrenzyArmor500 gp (3rd)2,000 gp (6th)6,000 gp (10th)

Source: Assembled from statistics in the Magic Item Compendium.