"Oro y Plata"

Since the creation of the first official seal for the Montana Territory, the motto "Oro y Plata" has been linked to Montana. Spanish for "gold and silver," the motto was chosen to reflect two elements that were vital to the Montana economy. Gold and silver are also representative of, among other things, the state's biggest universities, with the University of Montana's use of silver as a primary color and Montana State University's use of gold. Why wasn't "cobre" (copper), perhaps the most vital metal in Montana's history, also included? It's possibly because copper didn't become a major mining resource in Montana until large deposits were found in the 1880s, years after the motto was created.