Shatter is a passive level 17 Frostmage ability. It multiplies the critical strike chance of all the mage's spells against frozen targets by 1.5 plus an additional 25% (50% at level 36). A frozen target is a target immobilized by a frost-based effect, such as [Frost Nova], Freeze, [Freezing Trap] or the freeze effect from the [Freezing Band]. The critical strike chance applies to all of the mage's schools.
Freeze effects have a much higher chance to break when taking damage, meaning it can be difficult to get more than one spell to land on each freeze. It is still possible to get two criticals on the same freeze effect before it breaks. First, use a long cast time spell that also has a projectile travel time, such as [Frostbolt]. Immediately after the cast, use an instant spell such as [Ice Lance], if you are fast enough and at good range. The check to see if the target is frozen, and thus the critical strike check, is done at the time the cast completes, while the freeze effect is not removed from the target until after the spell hits. Thus, both spells will have the benefit of Shatter due to the time of flight for the first spell.
Now multiplies Critical Strike chance by 1.5 (down from 2).
Hotfix (2012-09-14): "The initial damage of Combustion is now properly affected by Shatter, increasing its crit chance accordingly."
Patch 5.0.4 (2012-08-28): Now available to all specializations as a passive ability. Critical strike chance multiplier reduced from 3 to 2, and has an additional 50% to critically hit. No longer increases the damage done by Frostbolt against frozen targets.
Hotfix (2010-11-23): "Shatter now only increases the chance for Molten Armor's damage to be a critical strike when the target is actually frozen, as intended."
Patch 4.0.3a (2010-11-23): Now also increases Frostbolt damage by 10/20% against frozen targets.
Patch 4.0.1 (2010-10-12): Changed from increasing critical strike chance of spells against frozen targets by 17/34/50% to multiplying the critical strike chance of spells against frozen targets by 2/3. Reduced to 2 ranks, from 3.
Patch 3.0.2 (2008-10-14): No longer has a prerequisite.
Reduced to three ranks, but kept the same effect at max rank.
Patch 2.1.0 (2007-05-22):Change from patch 2.0.10 changed back, however the overall chance that a freeze will break on any damage was still increased.
Patch 2.0.10 (2007-03-06):Freeze effects were changed to break much earlier when the target was critically stricken. Typically, a freeze effect such as Frost Nova will now break on the first critical strike.
Patch 1.11.0 (2006-06-19):Prior to this patch, the critical strike bonus only applied to frost spells. After this patch, Shatter applied to all of the mage's spell schools. This change made Shatter a viable talent combined with fire and arcane schools, especially in elementalist builds.