Xiuhcoatl

[2] Apparently, the royal diadem (or xiuhuitzolli, "pointed turquoise thing") of the Aztec emperors represented the tail of the Xiuhcoatl, the fire serpent.

Page 46 of the pre-Columbian Codex Borgia depicts four smoking Xiuhcoatl serpents arranged around a burning turquoise mirror.

The archaeological site of Tula has warrior columns on Mound B that bear mirrors on their backs, also surrounded by four Xiuhcoatl fire serpents.

[4] Although the Fire Serpent easily may be traced back to the Early Postclassic period in Tula, its ultimate origins are unclear.

The fragment was originally a part of a large stone disk that depicted the fallen Coyolxauhqui with the Xiuhcoatl fire serpent penetrating her chest.

An Aztec sculpture of Xiuhcoatl from Texcoco , now in the British Museum [ 1 ]
An Aztec sculpture representing the left-facing head of Xiuhcoatl
Huitzilopochtli as depicted in the Codex Borbonicus with Xiuhcoatl held up in his right hand as a weapon