I have two chunks from a copper mine I visited for a college course. Don't really know what to do with them. I
@Coyvan : What a gorgeous rock! Does it hold that color, or will it oxidize into drabness?
A shadow box on the wall might be a good location for that chunk or for both of them, a way to enjoy seeing them while protecting them in their natural form. Do you have a photograph from that day -- or of something relevant, even a photo of your textbook for that course -- that could be enlarged and used as the background in the shadow box?