Muonionalusta Iron Meteorite 2cm Cube, IVA Fine Octahedrite, Etched Widmanstatten Pattern

A 2cm cube of Muonionalusta, iron from the core of an asteroid

Muonionalusta is an iron meteorite recovered in northern Sweden and classified as a fine octahedrite of group IVA. This 2cm cube was machined from a larger mass and acid etched on all six faces, so the Widmanstatten pattern that formed in the metallic core of a differentiated asteroid is visible from every angle. Each cube weighs approximately 65 grams, with individual cubes varying by about half a gram.

The cube format turns a classic iron meteorite into a precise geometric object. Crisp machined edges frame the etched crystal structure, and the density of nickel iron gives a piece this small a weight that surprises anyone who picks it up.

Structure and features

Each face of the cube has been polished and etched to reveal the interlocking bands of kamacite and taenite that define the Widmanstatten pattern. Because the kamacite plates grew along the four octahedral planes of the original parent crystal, every face of the cube intersects those planes at a different angle. The band orientation shifts from face to face, so rotating the cube in hand shows the same three dimensional structure from six different cross sections.

As a fine octahedrite, Muonionalusta carries narrow kamacite bands that give the etched surfaces a tight, finely lined texture. The metal takes a bright etch with strong contrast between the lamellae, and the pattern runs through the full thickness of the cube rather than sitting on the surface.

Discovery and provenance

The first fragment of Muonionalusta was found in 1906 near the village of Kitkiöjärvi in the Pajala district of Norrbotten, Sweden, and the meteorite takes its name from the nearby Muonio river. The Meteoritical Bulletin Database lists Muonionalusta as an iron meteorite find from Norrbotten, Sweden. Additional masses have been recovered from the surrounding area over the past century, many pulled from glacial deposits, since the fall region has been overrun by ice sheets during repeated glaciations.

Scientific context

Iron meteorites of group IVA come from the metallic core of an asteroid that melted and differentiated early in solar system history. As the core cooled over millions of years, plates of low nickel kamacite grew within the surrounding taenite along the octahedral planes of the parent crystal. That intergrowth is the Widmanstatten pattern, and the timescale required to form it cannot be reproduced in any laboratory, which makes the structure itself evidence of extraterrestrial origin. The crystal structure preserved in this cube formed roughly 4.5 billion years ago. For a deeper look at how the pattern forms and why it matters, see the Widmanstatten pattern explained.

Frequently asked questions

Is the pattern natural or manufactured?
The pattern is natural. Etching with dilute acid only reveals a crystal structure that already runs through the metal. The geometry was set when the asteroid core cooled billions of years ago.

Why does the pattern look different on each face?
The kamacite plates follow the octahedral planes of the parent crystal, and each face of the cube cuts across those planes at a different angle. The result is a different band orientation on every face of the same specimen.

How much does each cube weigh?
Each 2cm cube weighs approximately 65 grams. Individual cubes vary by about half a gram, since each one is machined from solid nickel iron and finished individually.

Will it rust, and how should I care for it?
Muonionalusta is known for its stability among iron meteorites, but all nickel iron should be kept dry. Handle with dry hands, store away from humidity, and apply a light coat of mineral oil or microcrystalline wax if you live in a damp climate.

Collector significance

Muonionalusta is the reference iron for the Widmanstatten pattern in many collections, and the cube format is the cleanest way to display it. The shape sits naturally on a desk or shelf, shows the pattern from every viewing angle, and doubles as a tactile demonstration of nickel iron density. This specimen is offered by Treasure Coast Meteorite Co., IMCA Member #3323. Browse more iron meteorites in the collection.

Classification and provenance follow the official Meteoritical Bulletin entry for Muonionalusta, viewable at the Meteoritical Bulletin Database. Unless specifically stated in titles and descriptions, all meteorites sold by Treasure Coast Meteorite Co. are scientifically classified specimens with Meteoritical Bulletin citations.