Bauxite

Bauxite was a material found in Avignon. It is an aluminum hydroxide ore, a thermal conductor. It was useful for a fireplace.

It was seen in Map of Bones when Kat Bryant and Vigor Verona traveled to Avignon to search for clues of the Magi. Bauxite was mined in the region of Avignon and was named after the Lords of Baux, who claimed to be descended from a magi Balthazar.