The Muonionalusta is a meteorite classified as fine octahedrite, type IVA (of) which impacted the northern Scandinavia West of the border between Sweden and Finland, about one million years BCE. The Muonionalusta is probably the oldest known meteorite to man. Since landing this meteorite has experienced four ice ages.
The Muonionalusta meteorites are among the meteorites with the most beautiful etch pattern. Cut and etched, the interior reveals perfect Widmannstätten crystal structure. These lines are shown as a unique etched pattern on the meteorite. This pattern is the result of the meteorite cooling in outer space over billions of years. Although not as finely detailed as other meteorites, these pieces still display this pattern when cut and etched with acid. Sometimes inclusions like Troilite may be found. The exterior, when untreated, resembles a rusty bark. Interestingly some Muonionalusta meteorites are very weathered, whereas others are in really good shape for their high terrestrial age. Surely permafrost helped to preserve their state.