When you land a non-periodic critical strike with a Fire, Frost, or Nature damage spell, you enter a Clearcasting state.
The Clearcasting state reduces the mana cost of your next 2 damage or healing spells by 25%, increases spell damage done by 10%, and increases single-target healing done by 50%.
Elemental Focus is a passive shaman ability learned at level 40 for those with the elemental specialization. It grants a Clearcasting state after any critical damage spell (fire, frost, or nature) hits a target. The Clearcasting state lasts 10 seconds, reducing the mana cost of the next two spells while increasing spell damage and single-target healing.
0300Patch 3.2.0 (04-Aug-2009): Tooltip revised to indicate it does not work with critical strikes from periodic damage.
0200/0300Patch 3.0.2 (14-Oct-2008): Now also can proc off Lesser Healing Wave and Healing Wave, and can be used on all healing spells.
0200Patch 2.4.0 (25-Mar-2008): This buff will no longer be removed when Shamanistic Focus is triggered.
0200Patch 2.3.0 (13-Nov-2007): Now reduces the mana cost of the next 2 damage spells by 40%. Previously reduced the mana cost of 1 damage spell by 60%.
0200Patch 2.1.0 (22-May-2007): This talent now reduces the cost of the next damage spell by 60%. It will also now trigger from bonus spells cast by Lightning Overload.
0200Patch 2.0.10 (2007-03-06): The clearcasting effect from "Elemental Focus" now triggers on all spell critical strikes, rather than a chance on any spell hit.