Spell Components (V/S/M):
Vocal: Incantations (normally required in most BWG campaigns)
Somatic: Gestures (required instead of incantations in some BWG campaigns)
Material: Physical item representative of the spell being cast (not normally used in BWG campaigns).
Using V/S/M:
Vocal: All spells require an incantation.
Somatic: Gestures are treated like “Tools” if you cannot gesture you face double obstacles (wands, staves, daggers, and enchanted items do not hinder gestures).
Material: Something within the spell origin/area of Effect that either represents the element or impetus of the spell (a wand or other implement may suffice). Materials can be collected just like antecedents (by using alchemy or taxidermy to harvest it and stating what purpose it would be used for).
Spells cast without the proper material suffer an obstacle penalty (+1 Ob). Spells cast without an abundance of material may gain an advantage die to cast (+1D), like a fire spell that draws on a bonfire instead of a torch.
Materials are abstract and subject to interpretation of the gm and player.
All BWG spells are written as if all components are being used.
New spells (Abstractions) can add a minoris for Somatic Gestures, and one for Material Component.
adding either or both means you cannot cast the spell without them rather than just facing obstacle penalties.
(A Tip of the Hat to old school D&D)