Persian hymns suggest for me that Ahura Mazda may have been a fiery god.
The below silver dirham's obverse has the Sasanian king of Persia, Hormizd II who ruled ca. 303-309 CE. The reverse shows Ahura-Mazdah's bust facing left, wearing a Tiara/Crown, amidst the fiery flames of the Fire Altar. A Priest on the left and the King on the right flank the Altar (figure 83, Tafel 5, Robert Gobl. Sasanidische Numismatik. Klinkhardt & Biermann. Braunschweig. 1968)