Shape and Material Bonus
A Shape and Material Bonus is a bonus represnting the magical resonance between the shape or material being used and its intended magical function. S&M bonuses are applied in the manufacture of Enchanted Items, and in Talisman attunement.
S&M bonuses can be utilized through various other non-core means. These include the Potent Magic virtue.
It is well-established in canon that the core ArM5 list is not exhaustive, as it is augmented by various S&M provided in the supplements. It stands to reason that these lists are not exhaustive either, so the storyguide should feel free to invent and introduce his own S&M to the game.
It is possible, however, that certain S&M bonuses are known only to some magi. This is particularly relevant for those materials not prevalent throughout Mythic Europe (such as local types of trees) or simply rare ones (such as a dragon's egg). Counterintuitive correspondences might also fall under this category. The extent to which magi are aware of specific S&M correspondences is up to the troupe to decide.
It is usually assumed that all magi know the correspondences listed in ArM5, and probably all other official correspondences. Certain troupes allow the player to come up with other S&M bonuses and apply them on-the-spot, while others do not allow such at all or only allow the development of new S&M bonuses through Vulgar Alchemy.
Legacy Page
The history of this page before August 6, 2010 is archived at Legacy:shape_and_material_bonus