Meditation

Meditation is one of the two passive recovery skills along with Focus

Usage
Active use of the Meditation skill opens the Spell Memorization window; memorized spells are then cast using Magery.

Formula
Seconds per Mana recovered = 2 / (.1 * (2 + (Focus Skill / 15))

Other factors can also contribute to Mana recovery rate and are generally valued in increments of 15 Focus Skill.