Just seven meteorites have been found in Montana. Now offered is the main mass of Roundup, i.e., the largest existing specimen — and Roundup is the largest iron meteorite to call Big Sky Country its home…or rather, its second home.

Found in 1990 in central Montana near the small town of Roundup, only a single 17.8 kilogram mass was ever recovered. By way of comparison, there are several orders of magnitude more material originating from each of the Campo del Cielo, Gibeon and Seymchan events.

This sample originated from the molten core of an asteroid that had been shattered in an enormously energetic collision. When cut and etched, Roundup exhibits a medium-octahedral latticework of its two primary iron-nickel alloys, kamacite and taenite. This exquisite natural design is known as a Widmanstätten pattern, and different iron meteorites showcase different structures. An extended cooling rate of millions of years was required for the meteorite’s crystalline structure to form.
As this lattice-like matrix does not appear in man-made steel, its presence is diagnostic of iron meteorites.

On the reverse, variegated mango to chocolate hues wrap regmaglypts softened over time. An accent of the exterior surface is also seen at the front left margin of the cut face. “Rounding-up” this sale is the largest specimen of Montana’s largest iron meteorite. Accompanied by a custom armature. Modern cutting.

Christie's would like to thank Dr. Alan E. Rubin at the Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles for his assistance in preparing this catalogue.
239 x 121 x 61mm. (9.33 x 4.75 x 2.5 in.) and 4.84 kilograms (10.66 lbs)

Marlin Cilz Collection, Malta Montana