From Dungeons of Dredmor Wiki

1.0.2 - 14 mana, min cost 4, 4 blasting damage. Fireball effect - 5 conflag and 2 blasting. Flame field - 2 conflag dmg

1.0.3 - 16 mana, min cost 6, 4 blasting damage. Fireball effect - 2 conflag and 2 blasting. Flame field - 2 conflag dmg

-Zzinged forum post