It was a witnessed fall (1960) and is a rare type of achondrite-a stone meteorite which does not contain chondrules. Stone Meteorite: A 56.5-gram complete individual of the Millbillillie eucrite from Australia. Much of meteorite classification is based, in fact, on how much iron a Rocks, we usually discount anything that does not contain significant amounts of Rare that when we are asked for help and advice on identifying possible space Almost all meteorites containĮxtraterrestrial nickel and iron, and those that contain no iron at all are so Three main groups: irons, stones and stony-irons. The Three Main Types of MeteoritesĪlthough there are a large number of sub classes, meteorites are divided into Photo by Geoffrey Notkin, copyright Aerolite Meteorites. The Sikhote-Alin shower was the largest recorded witnessed meteorite fall in history. Its surface is covered with scores of small regmaglypts, or thumbprints, created by melting during flight. This fine specimen is described as a complete individual, as it flew through the atmosphere in one piece, without fragmenting. Iron Meteorite: A superb 1,363-gram complete iron meteorite from the Sikhote-Alin meteorite shower which occurred in a remote part of eastern Siberia in the winter of 1947. To stone meteorites, especially the most abundant stone meteorite group-the Though irons may be synonymous with most people's perception of a typical space rock's appearance, they are only one of three main meteorite types, and rather uncommon compared Very heavy, and have often been forged into unusual or even spectacular shapesĪs they plummet, melting, through our planet's atmosphere. It is often said that when the average person imagines what a meteorite looks The lattice-like structure is known as a Widmanstätten Pattern after Count Alois von Beckh Widmanstätten who described the phenomenon in the early 1800s. The slice has been etched with a mild solution of nitric acid to reveal an interlocking pattern of iron-nickel alloys, taenite and kamacite. It's the terrestrial mineral that is most often mistaken for a meteorite in the field.Iron Meteorite: Detail of a polished and etched slice from a siderite (iron) meteorite found in the Brenham, Kansas strewnfield in 2005 by professional meteorite hunter Steve Arnold. Be careful, as hematite (a common terrestrial iron oxide) is black, heavy for its size, and may also stick to a magnet. But most meteorite hunters use their "meteorite cane" - a magnet glued to the bottom of a long pole or walking stick - more as a tool to pick up potential meteorites than to definitively test a specimen. A chondrite's high nickel-iron content makes it adhere to a strong magnet. For this reason, meteorite hunters often use metal detectors in areas where meteorites are likely to be found. Nickel Iron: Most chondrites contain tiny flecks of nickel iron sprinkled throughout. Over time, they can literally cause a meteorite to crumble into pieces. All this expanding and contracting can causes stress fractures to appear on a meteorite's exterior within just a few years. In summer, moisture that has worked its way into a meteorite will cause it to contract, and in winter, when frozen, it will expand. But that's not the case on Earth, where a meteorite will begin to age as soon as it hits the ground. Stress Fractures: A meteorite can exist in outer space for millions of years without experiencing corrosion. This meteorite has been cut and polished to reveal nickel-iron flecks.
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