Changed from Classic: highlighted lines below differ between the two clients.
Classic 1.15.9.69722
Firestone
Binds when picked up
Unique
Held In Off-hand
Equip: Enchants the main hand weapon with fire, granting each attack a chance to deal 40 to 60 additional fire damage.
Equip: Increases damage done by Fire spells and effects by up to 14.
Forever Beta 1.60.1.70009
Firestone
Binds when picked up
Unique
Use: Imbues your weapon with Fire, increasing your spell critical strike chance by 1% and the damage done by your Fire spells by up to 14.