Diamond Skin

Diamond Skin is an Arcane spell used by s in Diablo III. Unlocked at level 8.

In-game
Encases the Wizard in diamond, absorbing unsaved damage. The diamond holds for up to 3 seconds, unless broken from damage earlier. Amount of damage absorbed is measured in percent of maximum Life.

Diamond Skin can be cast while stunned, frozen, feared or otherwise out of control. It does not end these effects, however.

The Illusionist passive triggers properly even if damage was entirely absorbed by Diamond Skin. However, absorbing damage with it does not prevent the Galvanizing Ward 5-seconds timer from being reset.

Runes:

 * Crystal Shell: doubles the amount of damage the diamond shield can absorb, to 80% of maximum Life.
 * Prism: while the Diamond Skin is active, Arcane Power cost of all spells is reduced by 9.
 * Sleek Shell: while active, Diamond Shield also increases movement speed by 30%.
 * Enduring Skin: increases duration to 6 seconds.
 * Diamond Shards: when Diamond Skin fades, either naturally or from damage, it explodes for 863% damage as Arcane in 10 yards radius.

Non-rune enhancements:

 * Dark Mage's Shade (Legendary Wizard Hat): automatically casts Diamond Skin when falling below 35% Life (15-20 seconds cooldown). This cooldown is separate from the normal cooldown of Diamond Skin, if the Wizard has one.
 * Ashnagarr's Blood Bracer (Legendary Bracers): increases potency by 75-100%.

Development
Diamond Skin was an essential part of the melee Wizard build before patch 2.0., as with the help of Critical Mass it could be used at all times, keeping the cooldown at zero. This allowed Wizards to effectively perform a tanking role.

Prior to 2.4, it absorbed a flat amount instead of percentage of Life.