• Type: Iron meteorite / IIIE-an
• Location: Xinjiang, China
• Weight: 14.8 g
• Size: 42 x 16 x 7 mm
• Year found: 1898
• Known total weight: 74 tonnes
• Surface treatment: Cut and Polished on multiple sides
• DETAILED DESCRIPTION

Aletai meteorite – The iron marvel from the IIIE group The Aletai meteorite belongs to the IIIE group, which is a specific type of iron meteorite. This classification comprises meteorites with certain chemical compositions and crystallographic structures. Meteorites from this group tend to display an octahedral structure, meaning that when cut and polished, they reveal the characteristic patterns known as Widmanstätten figures. IIIE meteorites, such as Aletai, are characterized by the presence of kamacite (low-nickel iron) and taenite (high-nickel iron) bands forming the octahedral pattern. Uniqueness of the Aletai meteorite Aletai is exceptional for the highest concentration of gold among IIIE group meteorites, and a significantly higher iridium concentration than others from the same group. Since the amount of iridium in meteorites is much higher than in the Earth's crust, the unusually high concentration of iridium found at the Cretaceous-Paleogene boundary 65 million years ago formed the basis of the theory that a massive meteorite impact may have been responsible for the extinction of the dinosaurs. Discovery and distribution The meteorite was discovered in 1898 in China’s Xinjiang region. The total mass found is estimated to be around 74 tonnes. The largest fragment weighs 28 tonnes, making it the fifth largest meteorite on Earth. The impact field covered an area up to 500 kilometers, initially causing discrepancies in identification and naming. Different names such as Armanty and Ulasitai were later unified under the name Aletai after chemical analysis. Mineralogy and visual effects An interesting feature is that as the angle of light changes, the reflectivity of the main alloys changes and the sample shimmers. This effect is typical for octahedral structures, but Aletai is particularly spectacular due to the presence of mirror-polished inclusions of the mineral schreibersite. Schreibersite is considered the primary source of phosphorus, which may have played a crucial role in the origin of life on Earth. It is composed of iron-nickel phosphide, with colors ranging from bronze to silvery white. This mineral is commonly found in iron meteorites such as Magura (Slovakia), Sikhote-Alin (Russia), Gebel Kamil (Egypt), and São Julião de Moreira (Portugal). The name derives from the Austrian scientist Carl Franz Anton Ritter von Schreibers, who was one of the first to identify this mineral.