Robert E. Longacre reports on a word in Proto-Mixtecan (spoken in Central Mexico c. 1000 BC) for "money" which also meant "bright, shining" and is related to "copper-colored."
Robert E. Longacre, “Proto-Mixtecan,” International Journal of American Linguistics 23, No. 4 (October 1957): 119
23. (*32 M *31) M-SM, SE, J, M, šu’ú money, bit (12 ½ centavos), M-SM, SE M šú’ú bright, shining; T za3 ‘aha 4-5 money, zaha3 bit, zi3-mi-2-1 (ču3h) yoke (of an egg); mi1-2 copper-colored, yellow. Pite syll: M T *θi