Incorrect information on page, it is identical in appearance to ancient armour helmet, the one shown in the picture is the female variant.
I've recently come across a bug relating to the Ancient Helmet of the Unburned. I'm running Skyrim ver. 184.108.40.206.6, with Dawnguard installed. I tried to equip the Ancient Helmet of the Unburned onto a mannequin in Proudspire Manor, Solitude. The inventory of the mannequin showed the helmet as equipped, but the helmet did not appear in the visuals. I tried re-equipping, reloading from the last save, and restarting the game. Same results. I had equipped the Vokun dragon priest mask, among other headgear, on that mannequin before, all of which displayed perfectly.