Where in the World are Grandpa and Grandma - moving west

The state we're thinking of is a big one.  It's very big in land mass but relatively small in population.  It was purchased from France and joined the union on 11/8/1889.  The early history of the state was concerned with mining - copper, lead, zinc, silver, coal and oil.  It's nickname is about something that could be made into jewelry.  The capital is a female name.  One large beautiful National Park has 26 glaciers, clearwater lakes and breathtaking mountain scenes.  Besides tourism, the state is known for raising grain, sheep and cattle.  The state's name is taken from the spanish word for mountain.  ..................Nonsense fact:  Try to picture a little big horn and you'll have the name of a famous battle that was fought in this state.