Focal stone (spell)

Focal stone was an alteration spell that transformed the structure of a clear or translucent gem stone, enabling it to receive the dweomer of a spell.

Effects
When cast, the gemstone would glow internally, radiating a faint dweomer. It could then be used as a focal stone or receive the life force from a magic jar spell. If it were then submerged in a poisonous liquid, it turn a vibrant purple color and could be commanded by touch to neutralize poison.

Components
The material component for this spell was a pinch of opal dust.