Black and White... Hm...
Well, Unodus has some good thoughts and I would like to throw in my own.
Black-Manipulation(NOT necessarily evil): Ability to take matter and reshape it within one's broad ideas. The specifics of each creation might escape the wielder, however, making it one of the most difficult weaves to learn. (If I wanted to build an ornate desk, I might just get a plain table). This could allow for some sort of "divine intervention" or subconscious telling conscious through weaves. The things it creates are always black. It is the most highly valued among abilities. This would be the most rare, as well, and as such there would be no specific vocation aligned with it.
White-Augmentation: White weaves reinforce objects, making them impossible to manipulate with black weaves, also making them more durable in the physical sense. Not only are things more durable, but they complete the intended action more usefully. This could be used for artisans and carpenters, and would be highly valued in construction.