An insane sorcerer of supreme power, whose name is lost to antiquity, is rumoured to have created these delightfully destructive little nuggets of fiery doom. By using his mastery of metamagic, he could crystallize an intensely powerful fireball a fraction of a second before it would detonate. This crystallization suspended the fireball in time until the crystal was shattered, upon which it released its full force destructive power.
A creature can use an action to throw the crystallized fire up to 60 feet. The crystallized fire explodes on impact and is destroyed. Each creature within a 20-foot radius of where the crystallized fire landed must succeed on a DC 21 Dexterity saving throw or take 34d6 fire damage. If the crystallized fire is ever directly subjected to damage, it explodes instantly. In addition, if a creature carrying or wearing the crystallized fire is ever subjected to force or thunder damage, there is a 5% chance that the crystallized fire will crack and explode within 1d3 rounds. If the crystallized fire is worn or carried by a creature at the time of its explosion, the creature automatically fails the saving throw against the damage of the resulting fireball.
Notes: Damage: Fire, Damage, Consumable
34d6? This would be much more interesting with lower damage