This rare slice of the Muonionalusta meteorite, found in 1906 in Norbotten, Sweden, shows a classic example of the Widmanstatten pattern. Widmanstätten patterns, are figures of long nickel-iron crystals. They consist of a fine interleaving of kamacite and taenite bands or ribbons called lamellae. Commonly, in gaps between the lamellae, a fine-grained mixture of kamacite and taenite called plessite can be found.
The Muonionalusta is a meteorite classified as fine octahedrite, type IVA (Of) which impacted in northern Scandinavia, west of the border between Sweden and Finland, about one million years BCE. The first fragment of the Muonionalusta was found in 1906 near the village of Kitkiöjärvi.