Søren Wichmann shows that the Mixe-Zoquaean language had a word for "metal."
Søren Wichmann, The Relationship among the Mixe-Zoquean Languages of Mexico (Salt Lake City: University of Utah Press, 1995), 564
fierro, metal pZ *ti?|]-kuy (n)
Ti#059
As noted by LDS scholar Brant Gardner:
Linguistic data provide hope that archaeology might yet make a discovery that would alter our understanding of metallurgy dating in Mesoamerican. The word for metal has been reconstructed in the Mixe-Zoquaean vocabulary (*ting-kuy). This is the language group that would have been spoken during Jaredite times. It is therefore certain that there was metal, else there would be no reason to have the word. However, it could have referred to iron ore and not to smelted metal. Confirmation of early metal-working is still absent. (Brant A. Gardner, Traditions of the Fathers: The Book of Mormon as History [Salt Lake City: Greg Kofford Books, 2015], 184)