For wizard and witches magic has to be gathered through their magical core and then refined into ready magic.
The System Edit
Magic is a form of energy, which certain living things can store and use to manipulate reality. It exists all around in the DP&SW universe in another plane of existence, which is called the aether. The aether does not interact with physical things in any way. The only way the aether interacts with the magical people is through a thing which some living things possess, called a core.
The core absorbs raw magic from the aether at a constant rate and stores it. When magic flows from the core into the bodies, the core converts it into a more usable form, what is called ready magic. But by doing the transformation from raw magic to ready magic, also a toxin is produced which the magical body flushes out from the system as quickly as it can.
It is difficult to use ready magic throughout the human body, because it has a very high natural reluctance. To combat that natural reluctance a wand is used. In the end one has the magical system from aether, to core, to body, and finally, to wand.
Magical visualization Edit
A spell is ready magic with intent. The visualization or intent, when first time using a spell it is vert important and determines how good a spell works out. For the visualization wand motions, incantation, runes and similar are used. By constant repetition of usage, one could take it as far as casting the spell without wand motions, without speaking the incantation or even doing it completely wandless. It is faster to learn to do it wandless, when Occlumency is applied.
[ v ]Human magic
|Wand based||Alchemy · Charms · Duelling · Transfiguration · Wand lore|
|Wandless||Enchantments · Herbology · Necromancy · Potions · Rituals|
|Mixed||Divination · Healing · Magical theory · Mind magic|