Arcane Magic

Arcane magic is the term given to the magic wielded by wizard and sorcerer. It comes directly from the silver weave which is governed by Mystra. Wizards use this raw energy for their spells, every delicate flourish, every shrill word, every painstaking rune dictates what the raw energy shall become the difference between a fireball and a light cantrip could be just a degree in the left hands flourish.
The nature of the weave is what you make of it. Should you be fickle with the weave so shall the weave be fickle with you. Magic is essentially law applied to chaos. The chaotic element being the silver weave and the element of law coming in the form of verbal and somatic components performed by a caster. Some spells also require a material regent to cast, usually the flow of the weave destroys the object in the process.
To access the silver weave it is a simple process of learning the proper incantations and ways to train your mind to deal with the amount of energy it will be exposed too. The Arcane weave is unpredictable it can effect and change the physical world around you from a subtle change that you will never even notice to reducing a mountain to rubble. The greater the spell cast the more of the silver weave you shall expose yourself too thus meaning a greater more learned mind is required.