Rules: Property Knowledge must be purchased for a specific property (Influence, Healing, and so on). You must have Property Knowledge of a specific property to improve a spell with that property above SR 14. In addition, you can use modifications on activated spells from an unfamiliar Tradition which have that property. To purchase Property Knowledge for a specific property, you must know three spells with that property at a SR of 10 or higher, and must spend time studying the peculiarities of the property (for example, by conducting research at an academy that specializes in the property, or by finding a tutor experienced in the property). Once you purchase Property Knowledge for a specific property, there are no special limitations for improving spells with that property other than the usual maximum for skills (see page 351).
Primary attribute of the Tradition 15, 3 enchantments with the property at SR 10 or higher.
AP Value: 10 adventure points for the first Property Knowledge, 20 adventure points for the second, 40 adventure points for the third.
Publication: Core Rules page 285