There is a museum in Houghton, Michigan, the A. E. Seaman Mineralogical Museum. Couple that wonderful experience with a trip to the Keweenaw mines where you can purchase a slag pile of your very own and you can keep whatever you find. The mines allow a person or a group to purchase a three yard pile of slag. Bring your own rock hammer. The piles contain datolite, chrysoberyl, chrysoprase, thompsonite, copper, agate, garnet. I am going to look for a mine that does it and include a link. The slag heap costs 200 dollars. I took my wife and our adult son and his wife. You will get dirty and perhaps find your own samples. I will add the mine site when I find it.