Citrine

Citrine is the rarest of the 8 Infusable gemstones. It can be Infused by hanging it outside during a thunderstorm and exposing it to the light of a stormbolt. Infused, it has a variety of uses:
 * Herblore: grants greatly increased speed.
 * Weapon: can make a foe flinch by generating a bolt of thunder when striking.
 * Shield: returns part of the damage taken to the attacker.
 * Self-Infusion: greatly reduced weight.
 * When forged into a vehicle, it greatly reduces its weight.
 * Infused Citrine can pass on its infusion by gently tapping it against an uninfused gemstone. This process is irreversible and does not work on uninfused Citrines.