Meteorite Muonionalusta – Norrbotten, Sweden

The Muonionalusta meteorite fell to Earth an estimated one million years BC, making it one of the oldest known meteorite falls. It is classified as a fine Type IVA octahedrite and is known primarily for its beautiful Widmanstätten patterns, which are the disordered structures of the iron-nickel crystals that make up the meteorite. To see these patterns, the surface of the meteorite must be polished and then etched with dilute nitric acid, preferably with methanol. However, not all iron meteorites have these patterns.