Elemental Magic is the magic of fire, earth, air, and water. Most Elemental Magicians know a few spells from each group; it'd be very rare to find an Elementalist who ONLY knew fire spells, for example. Normally, one would have one element s/he is most proficient in, then the second-best, etc. etc. It is possible to be equally proficient in two elements. It's highly unlikely to be equally proficient in three, and nearly impossible to be equally proficient in all four.
Like all magic types, to be an Elementalist is to learn and memorize set spells. Focus is important, because an unfinished spell can have any sort of good, bad, or wacky results.
Elemental Magicians (or Elementalists, as most prefer to be called) primarily manipulate the quantities of that element that are around them (and yes, this does include things like: water in the air, water in the human body, air in the human body, etc.), but, can, if they reach a sufficient level, create small quantities of elements.
Elemental Magic's downfall is cold iron. Iron dulls the purity of the interaction between the Elementalist and the elements themselves, and even absorbs some of the energy of Elemental attacks. Wearing or carrying iron on one's person is a surefire way to reduce the effectiveness of Elemental attacks - even if you're the one casting it.
There's one good reason not to pick elemental magic: it can be damn complicated.
Decide which element is your primary; you'll have to provide a good reason to be equally proficient in two, and if you want three at equal strength, your reason had better be DAMN good. Rank the four elements in order from best to worst.
Even a Level 1 neophyte can still see a green sort of "glow" outlining objects or people strong in Elemental magic or under the influence of an Elemental spell, but cannot detect the "aura" or "glow" of other magic types unless they've also studied those. The "glow" is not visible on oneself unless one is actively working magic at the time, and fades when the spell is cast or otherwise ends.
As with most magic schools, you buy your Level of magic with points. In the case of Elemental Magic, your level is equal to the level of defensive spells you can cast, and your level - 1 is equal to the level of offensive spells you can cast. Focus required for each spell is equivalent to the spell's level (thus a level 5 spell takes 5 Focus to cast). However, Elemental magicians have a special ability no other school has, that they learn at level 8, which can temporarily increase a magician's focus.
Levels & MP costs as follows:
There are no healing spells in Elemental Magic, although they can be used to soothe (for example, cool water on a burn).
Casting Time increases with the level of the spell being cast. To figure out how many turns it takes to cast a spell, divide the level of the spell in half (and round down if necessary). So levels 1, 2, and 3 have a casting time of 1 turn, that is, when you say, "I cast [Name of Spell]", the spell is cast in that turn. Levels 4 and 5 have a casting time of 2 turns, so the turn after you declare you're casting it, it goes off. Levels 6 and 7 have a casting time of 3 turns, so two turns after you declare you're casting it, it goes off, etc. etc.
Here's how buying Elemental Magic works. You will have to buy EACH SCHOOL you are interested in; your MP is equal to the point cost of your Primary school x 2. Pick an elemental school as your primary. It costs 2 points each to buy levels 1-3, 3 points each to buy levels 4-7, and 4 points each to buy levels 8-10 (for a total of 30) - for your primary school only. Now, look at your element's opposite. Naturally Water and Fire oppose each other, as Earth and Air do. Water spells can therefore counter Fire ones, etc. etc. But more importantly, it will be TWICE as much (per level) to raise the element that is the opposite of your primary. Thus, if your primary is Air, and you want to be level 5, it will cost you 12 points to be level 5 (2 points each for 1-3, 3 points for level 4 and 3 points again for level 5) and you'll have 24 MP; if you then choose to take Earth as your secondary school and want it to be level 4, it'll cost you 4 points each for levels 1-3 and 6 points for level 4, for a total of 18. The breakdown is as follows:
Just to clarify, if you want to learn all four schools of Elemental Magic, you're going to end up spending 170 points: 30 for your Primary, 60 for the Opposite of your Primary, and 80 total for the other two. Your Opposite Element doesn't have to be your Secondary - that's just an example. You can decide not to learn it at all, if you want. You don't have to learn multiple schools, for that matter (though it can be useful to you as you advance). Learning all there is to know about Elemental magic is a long, hard, and expensive process, but can pay off very nicely if you keep at it. The decision is, of course, up to you.
As far as cold iron goes, here's what you can expect:
When wearing/carrying cold iron:
When casting magic onto cold iron: