Kaalijärv Iron Meteorite Slice, IAB-MG, 27.00g, Neumann Bands

Bronze Age impact site specimen with visible shock features

This 27.00g slice from Kaalijärv reveals linear Neumann bands cutting through the kamacite lamellae of its Widmanstätten pattern. The bands appear as parallel lines that intersect the typical octahedral structure, documenting shock pressures from high-velocity collisions that preceded the meteorite's final impact on Saaremaa Island approximately 3,500 years ago.

The etched surface exposes the intergrown kamacite and taenite structure characteristic of medium octahedrites in the IAB complex. The presence of well-defined Neumann bands across multiple kamacite plates indicates shock metamorphism occurred while the parent body was still intact in space, prior to the atmospheric entry that created Estonia's Kaali crater field.

Shock deformation structure

Neumann bands form when shock waves exceeding 13 GPa propagate through kamacite crystals, creating twin planes along specific crystallographic orientations. In this specimen, the bands manifest as straight, parallel features that maintain consistent orientation within individual kamacite lamellae but shift direction at taenite boundaries.

The Widmanstätten pattern itself formed during cooling rates of approximately 1-10°C per million years within the metallic core of a differentiated asteroid. The intersection of slow-cooled structure and rapid shock deformation creates the layered geological history visible in this slice.

IAB complex formation and crater field context

IAB-MG meteorites represent a medium octahedrite subgroup within the IAB complex, a non-magmatic iron group that likely formed through impact-melt processes rather than fractional crystallization. The parent body experienced catastrophic collisions that mixed metallic and silicate components before re-solidifying.

Kaalijärv material originates from the Kaali crater field impact, which occurred during the Bronze Age when human populations occupied the region. The nine-crater field on Saaremaa Island represents one of the youngest confirmed meteorite impact sites where material has been recovered and classified. To understand how impact structures preserve meteorite fragments, see How to Tell if a Rock is a Meteorite.

Frequently asked questions

Is this meteorite authenticated? Kaalijärv is classified as Iron IAB-MG in the Meteoritical Bulletin. You can verify the classification through the MetBull database search. This specimen includes a certificate of authenticity documenting its classification and provenance.

What are Neumann bands? Neumann bands are shock-induced deformation twins that form in kamacite when iron meteorites experience impact pressures above 13 gigapascals. They appear as parallel lines within individual kamacite crystals and serve as geological records of violent collisions in space.

What is included with this specimen? This listing includes the 27.00g etched slice and certificate of authenticity. No display stand is included.

How old is the Kaali impact? Radiocarbon dating and stratigraphic analysis place the Kaali crater field impact at approximately 3,500 years before present, during the Bronze Age. This makes it one of the youngest documented meteorite impact events with recovered material.

Why does the classification include "MG"? The MG designation indicates "medium" bandwidth in the octahedrite classification system, referring to kamacite lamellae widths between 0.5 and 1.3 millimeters. This structural parameter reflects the specific cooling history of this IAB complex specimen.

Documented impact site material for iron collections

Kaalijärv specimens combine structural iron meteorite features with direct association to a documented terrestrial impact site. The presence of Neumann bands adds a shock metamorphism component that distinguishes this material from unshocked IAB specimens.

This slice displays both the crystallization history recorded in its octahedral structure and the shock history preserved in its Neumann bands. The 27.00g format provides sufficient surface area to observe the intersection of multiple kamacite plates and their associated shock features. Collectors building comprehensive iron meteorite collections value Kaalijärv material for its combination of known terrestrial context and visible shock deformation.

Meteoritical Bulletin entry: Kaalijarv | Classification: Iron IAB-MG | Find, Estonia, 1937