Octahedrites are the most common structural class of iron meteorites. The structures occur because the meteoric iron has a certain nickel concentration that leads to the exsolution (when a solid solution becomes unstable) of kamacite out of taenite while cooling. Due to a long cooling time in the interior of the parent asteroids, these alloys crystallize into intermixed millimeter-sized bands (from about 0.2 mm to 5 cm). When polished and acid-etched, the classic Widmanstätten patterns of intersecting lines of lamellar kamacite, are visible. In gaps between the kamacite and taenite lamellae, a fine-grained mixture called plessite is often found. Graphite and troilite occur in rounded nodules up to several centimeters in size. Offered here is a 1.75x2-7/8x1" tall coarse iron octahedrite meteorite that weighs 198.7 grams. This meteorite fell in Sikhote-Alin, a mountain range in Primorsky and Khabarovsk Krais, Russia. This meteorite fell Feb. 12, 1947 as part of one of the largest meteor showers in recent history. The Sikhote-Alin meteorite exploded in the atmosphere as it fell, raining many tons of metal on an elliptical region about one mile in area. Craters were formed by the meteors, the largest being 85.3' in dia. This is a complete "natural" specimen, showing flow lines and its original weathered surface, which is covered in oxidation given the high iron content of this meteorite. Makes for an out-of-this-world display. From the Robert M. Overstreet Collection and comes with COA.