Jewel of the Firelord

Jewel of the Firelord is a cosmetic helm.

Source
This item is available for purchase from the shop for $15 or €15. It was released on July 17, 2013.

With the See You Later Bundle on December 20, 2019, this helm was available at a discounted price with other items. On January 19, 2019, the helm is no longer available for purchase as it entered hibernation in the Blizzard Archive.

Blizzard Shop
''Salvaged from the remains of the fallen minions of Ragnaros the Firelord, this helm sets you apart as a glowing beacon on an otherwise crowded battlefield. Where’s the rally point? How about by that guy with the RAW ELEMENTAL FIRE emanating from his forehead?''
 * Fiery and functional