Associations: Responsibility, stubbornness, inflexibility, strength, pragmatism, empathy. Growing, nourishing, protecting, blocking. Scent.
General earth powers focus on rocks and soil. Tearing up stones, creating walls from the ground, shaking the earth to throw off an enemy's footing, and so on are techniques commonly employed by traditional earth users. Used internally, earth powers augment strength and endurance. The most common passive earth ability makes the user extremely sensitive to vibrations in the ground (earth or metal). Another might be to sense life itself, allowing an earth user to detect plants, animals, and humans by their animating force.
Metal is a subcategory of earth in which the wielder is more comfortable with ore than other rock. Those who specialize in it have a much easier time shaping pure or worked metal than other earth wielders, and can often alter subtle things like density, heat capacity, or conductivity. They also have a greater or lesser control over magnetism, and some can passively sense magnetic fields.
It has been theorized that a metal affinity arises when an earth wielder also has some affinity for fire.
Plants are a subcategory of earth in which the wielder can cause green things to grow, both unnaturally swiftly and to sizes they could not attain biologically, and move rapidly. Plant users can more subtly affect plants, causing changes in them that are lasting and will be passed on to their offspring, although it takes a longer time for changes that are not only permanent but self sustaining. Some plant users can passively sense plants, and use their powers to get an idea of an unfamiliar plant's properties.
It has been theorized plant affinities are a result of earth tainted with water.
The natural extension of this is that there should be some earth subcategory stemming from the influence of air. Control over animals seems a likely result of this. I would guess an earth wielder with an animal affinity would be able to communicate in a limited way with lower life forms, and possibly coerce or suggest courses of action to them; possibly they would form a particularly strong bond with a specific animal, giving rise to old stories of witch's familiars. We have yet to see anything like this in play.
Earth can also be used for healing, usually in conjunction with a plant (or animal?) affinity. Healing with earth is usually strongly assisted by herbs and poultices, and is not so much quicker than natural healing as better – more thorough, and more effective for even the most drastic wounds.
Associations: Adaptability, compassion, persistence, apathy, ambivalence, mutability. Changing, healing, calming, emotion. Touch.
General water usage focuses on the moving and shaping of water. This is best when a source of water is around, so great waves and jets of it can swamp or unseat and opponent, but any water user worth their salt can also condense water from the air in all but the driest of environments, and use the small quantity as a storm of tiny, high-velocity projectiles. Traditional water training generally includes enough practice in healing to deal with bruises, cuts, or first aid. Used internally, water magic is well balanced, increasing both strength and grace, although it is not as effective offensively as earth, nor as effective defensively as air. Passively, most water users are aware of any concentration of liquid near to them at all times, giving them an easy way to detect humans; however, water users raised to the old ways learn how to shield their blood from being sensed by other water users at an early age.
Ice is the water affinity that manifests most often, allowing a precise control over the temperature of water. Ice wielders can create much more effective weapons, which depend on keen tips as much as speed to penetrate an opponent's body. Ice wielders can also heat water, causing it to evaporate, and control the resulting steam, so 'ice' is actually a bit of a misnomer. Ice wielders occasionally manifest a fire-like ability to passively sense heat, although they are limited to the heat of liquids.
Ice affinities probably arise from a taint of fire.
Healing is the very broad water affinity theoretically resulting from a hint of earth affinity in a water user. In the most general sense, it is a tuning to living things; but unlike the earth plant or animal affinities, it is focused on the individual processes of a body rather than the whole. Most healers employ their skills for others. Water healing is the miraculous healing which can repair a grievous wound in a matter of minutes. However, a healer who uses their power internally is a nearly unstoppable fighting machine, since so long as they have magical energy, they can repair any damage they take almost instantly. So-called 'blood-bending' is usually another manifestation of healing, allowing a water wielder to manipulate the liquids within living things, although some approach blood-bending from another angle by simply refining their control over fluids other than water.
We haven't seen it, but theoretically a water user might have an affinity for 'emotion' or something similar, and be able to sense and manipulate, not coherent thoughts, but human emotions and feelings. This would be water tainted with air.
Weather control requires equal parts air and water, and is best attained with the aid of a fire wielder as well. Theoretically, any of those three might be able to exercise a very crude and imprecise control over weather.
An aside – water users often feel that the moon is related to their element, possibly because of its relation to tides. Whether the effect is psychosomatic or mystical, water wielders do seem more powerful and energetic when the moon is full, and less so during a new moon or lunar eclipse. Some say months with a 'blue moon' are best for complicated water workings, although others argue that's stupid, since months are a human invention and people ought to be on a more stringently lunar calendar anyway.
Associations: Temper, passion, quickness, violence, caprice, wildness. Heat, light, purification, consumption. Sight.
General fire usage involves creating and controlling fire. Starting, shaping, and putting out flames allow for a wide variety of destructive attacks. Heat can also be controlled, an object being warmed (or cooled) without actual flames being involved. Using fire magic internally increases dexterity, granting the user an almost precognitive ability to dodge attacks and find openings to strike. It can also be employed to raise or lower the body temperature of the user, as a whole or selectively; fire users are very difficult to kill by their own element. The most common passive fire ability allows a fire wielder to sense the temperature of their surroundings, easily identifying body heat.
Electricity is the subcategory of fire thought to result, in various circles, from a tainting by earth or air. It can be used for anything from destructive lightning bolts to powering an appliance. Some electrically affiliated fire wielders claim to be able to sense and even manipulate the subtle electric fields of human and animal minds, but it seems as though that might be its own specialization. If it is, however, a mastery of electricity, then it suggests the electrical affinity arises from air rather than earth taint.
Illusion is another subcategory of fire, and involves the very subtle creation and bending of light. Illusionists can, at the most basic level, summon light in darkness, or create an area of darkness where there should be light. More advanced illusionists can create phantasms, although such creations, if purely made of fire, have no somatic or tactile components, being mere three-dimensional images; illusionists can also disguise themselves or others, altering hair color, facial features, etc. Illusion is probably a tainting of fire with water.
Fire can be used for healing in a limited way, by purging wounds of foulness or burning off infection. While it does not patch or mend directly, it can prevent things from getting worse, and sometimes provide the body with more energy for healing itself.
Fire is strongly associated with the sun. Most fire wielders consider themselves much stronger during the day, and consequentially, they prefer to wage war during the daylight hours. When fighting the fire tribes, one does not usually have to guard against an attack under the cover of darkness.
Associations: Intellect, irresponsibility, wit, flightiness, speed, inconsistency. Thought, motion, perception. Sound.
Air used externally is good for burst attacks; wielders are trained in shaping wind, either into large, flattening gusts or sharp edges. Moving air aside to create vacuums is sometimes used as a defensive trick, particularly against fire attacks. Used internally, air magic increases agility, although not quite to the level that fire magic does; it is, however, a more sustainable quickness, since it makes the wielder functionally lighter and oxygenates the blood, preventing them from becoming winded. More mobility and acrobatics, less near-prescient dodging and attacking. Air users can passively perceive 'psychic noise'; all can read the auras of elementals with varying levels of aptitude, allowing them to identify elemental affinities and strengths of other wielders. Most conventionally trained elementals, however, know how to contain or otherwise hide their auras when they are not actively using magic.
Since auras are not 'real,' all air users tend to perceive them differently. Most have a sense that they interpret auras as registering as; most see or hear auras, but some smell, feel, or perceive them in an even more abstract way.
Flight is not really a subcategory of air, but it comes naturally to some air wielders, and at great difficulty to others. It can either be achieved externally, by changing air pressures to lift you, or internally, by lightening and lofting one's body.
Telepathy / metamagic is possibly the most common air specialization, and so broad that some consider it to be two different subcategories. Telepaths are usually more passively sensitive to auras than other air wielders, and many can also passively sense other psychic noise, including that produced by magic in use, magical items, 'places of power', or even thoughts directed at them with sufficient intent. Telepathy mainly encompasses the entering of people's minds and reading and rearranging their thoughts; metamagic deals with containing, deflecting, or amplifying the magic of others directly (rather than the effects of that magic. Usually telepaths exhibit some metamagic capabilities and vice versa, although it is extremely rare, if not unheard of, to find an elemental who is strong in both.
Both earth and fire have been suggested for the influences that would cause an air affinity to bend towards telepathy and metamagic. It has also been theorized that telepathy is actually the basic form of air magic and conventional air shaping is a result of that being polluted, but very few circles take this seriously.
Sound manipulation might be another subcategory of air magic, a very precise creation and manipulation of pressure waves. It is the audible analogue of the illusions some fire wielders specialize in, although the most popular theory is that it originates from a taint of earth affinity in an air user, since some sound wielders can sense vibrations in gasses passively the same way earth wielders sense vibrations in solids.