Wizards who are earth specialists focus on the application of earth, stone, and rock—with a special emphasis on caustic salts—within all schools rather than studying one school of magic, as most wizards do.
You gain a +1 bonus on attack and damage rolls if both you and your target are touching the ground. You also gain a +1 bonus to your CMD if both you and your attacker are touching the ground. At 10th level, these bonuses increase to +2.
At 6th level, as a free action you can make a Knowledge (Arcana) check anytime you are within 30 feet of a creature of the [earth] subtype to learn its type and all subtypes, including any information gained from a Knowledge check appropriate to its type. The DC of this check is 10 + the creature’s CR.
You also make a Knowledge (arcana) check as a free action whenever anyone within your line of sight casts a spell with the [acid] or [earth] descriptors. The DC of this check is 15 + the spell’s level. On a successful check you know the name, level, and general effect of the spell being cast.
For any spells you learn with the [acid] or [earth] descriptors, you gain the benefits of the Eschew Materials, Spell Mastery, and Spell Focus feats. At 12th level, you also gain the benefits of Spell Penetration with these spells. You do not need to actually have these feats to gain these benefits, and the benefits do not stack if you also take the feats for these spells.