Plotinos: Complete Works, v. 1 In Chronological Order,...

Qualities, therefore, are everything that, instead of being actualizations and forms of beings, are only its accidents, and only reveal its shapes. We will therefore call qualities the habituations and the dispositions which are not essential to substances. The archetypes (or models) of qualities are the actualizations of the beings, which are the principles of these qualities. It is impossible for the same thing at one time to be, and at another not to be a quality. What can be separated from being is quality; what remains united to being is being, form, and actualization. In fact, nothing can be the same in itself, and in some other condition where it has ceased to be form and an actualization. What, instead of being the form of a being, is always its accident, is purely and exclusively a quality.