Elements
All spells in wizardry have an element, as do many wizards, wands and sets of wizard armor. Elements are woven into every aspect of magic: they describe the nature of spells belonging to them, determine how magic interacts with different creatures and environments, and create synergy between certain spells, wands and armor. There is much to be gained from specializing into a single element, though this is by no means the only path a wizard can take.
Magic
Magic is not really an element in the truest sense. It exists firstly because of non-elemental wizards, wands and wizard armor, and secondly as the element for the magic missile spell. Spells and items associated with the element of magic show no particular alignment to any of the other elements.
Fire
Fire does exactly what one might expect - it is first and foremost a powerful attacking force, giving wielders of fire spells the power to set targets alight, dealing damage to them over time. Pyromancers leave nothing to chance, preferring to incinerate their foes directly, though a few have perfected the art of summoning fire spirits. Fire spells are very effective on most unarmored overworld mobs, especially creatures of ice and frost. Conversely, fire spells have little to no effect on nether-dwelling creatures. Fire is not just a weapon though - sometimes it can serve as a useful tool or even a defense as well.
Ice
Whilst it lacks the sheer power of fire and lightning magic, ice magic is more effective than it may seem and offers a unique set of abilities. Central to the effectiveness of ice spells is their ability to slow down their victims, giving their caster a significant advantage in combat. Ice mages are difficult opponents indeed, and should they be angered, one may find oneself struggling against debilitating frostbite effects while being showered with razor-sharp ice.
Lightning
No other element embodies raw power quite like the element of lightning. Storm mages are capable of channelling this power from the heavens and focusing it into powerful attacks, including that most enigmatic of abilities - to summon bolts of lightning at will. Powerful storm mages can even influence the weather as well as channelling it. Power, however, comes with risks: lightning spells almost always cause creepers they hit to become charged, so be wary when fighting them.
Necromancy
A mysterious and often mistrusted form of magic, necromancy is dominated by summoning spells, giving necromancers the ability to summon various undead mobs as well as more powerful elemental beings. Necromancy may also be used to influence creature's minds, inflict withering effects and manipulate life forces. Necromancers seek to control, preferring to stand at a distance while their minions exact their will upon the world. Fighting against a necromancer means having to fend off hordes of undead mobs whilst dealing with the effects inflicted by the necromancer themselves.
Earth
Earth is a broad element with a broad range of abilities to match. Earth magic can be loosely divided into 3 categories: animal-based magic, plant-based magic and magic based off of the physical elements - rock, water and air. The abilities offered by earth magic include summoning spirit animals, inflicting poison effects upon victims, and manipulating wind and water - to lethal effect. Earth mages are unpredictable and can use all manner of spells to attack, confuse and fend off their opponents, as well as take on supernatural abilities.
Sorcery
Widely believed to be the most ancient form of magic, sorcery is the name given to a collection of spells which form a direct connection between their caster and the laws of reality. Sorcery spells can be loosely divided into 3 types: motion spells, conjuration spells, and alteration spells. Sorcery spells can be used, for example, to create light, move objects at a distance, and conjure blocks and items. Powerful sorcerers focus bolts of arcane force at their adversaries, teleport around at will and even tear holes in the fabric of reality. It is even rumored that there exist spells for manipulating time itself - however, for now at least, these spells are lost somewhere in the past.
Healing
Healing differs from the other elements in that its primary focus is on defense. Healing spells are indispensable when in combat, and nearly all wizards know at least a basic healing spell. However, those that specialize into healing gain access to a much greater variety of defensive, and on occasion, attacking spells. These include more powerful healing and regenerative abilities, summoning magical shields and wards, neutralizing opponents' attacks and granting resistances. A number of healing spells are also ally-based, making healers a very useful addition to any adventuring party. Fighting a healer is a tough challenge due to their sheer tenacity - if you are not careful, you can end up effectively defeating yourself.