By Gregory T. Shanos with heat-altered, barely visible mateur astronomers enjoy chondrules is a 6. For example, observing objects in the an H3 chondrite is high-iron with universe from afar, holding well-preserved chondrules, and Anightly vigils at the telescope, an LL6 is a low-low-iron collecting ethereal photons chondrite with thermally altered exhibit a crystal pattern called a matrix. Mesosiderites consist of with our eyes or with CCD chondrules. The ordinary H, L, Widmanstätten pattern when broken, angular fragments of cameras. Unbeknownst to many, and LL chondrites are also sliced, polished, and etched with mantle rock and nickel-iron that there is also a way to collect sometimes called olivine-bronzite nitric acid. Hexahedrites show have been fused together by “rock solid” representatives of the chondrites, olivine-hypersthene thin, parallel Neumann lines impact. Solar System, in the form of chondrites, and amphoterites, when etched. Ataxites show no All meteorites—except meteorites. Starting a meteorite respectively. Widmanstätten pattern or interior pieces of those that collection is a rewarding and Achondrites appear to have Neumann lines, because of their broke apart after passing educational pursuit. The following been chondritic before being high nickel content. through the Earth’s atmo- essay is a compilation of over 30 altered by heat or impact. The Iron meteorites are subdivided sphere—exhibit fusion crust on years of experience that I have HED (howardite, eucrite, and according to a chemical their exteriors. Fusion crust is gained in the art of collecting diogenite) achondrites are classification system using nickel a black, melted outer coating, meteorites. confirmed to have originated from and the trace elements gallium, which is evidence of atmospheric There are three basic types of the asteroid (4) Vesta (Figure 2). germanium, and iridium to define entry (Figure 3). Meteorites are meteorites: stones, irons and Other classes of achondrites distinct chemical groups. These designated as falls or finds. A fall stony-irons (Figure 1). Stone include acupulcoites, angrites, groups are named IAB, IC, IIAB, is a meteorite that was actually meteorites comprise 92 percent aubrites, brachinites, lodranites, IIC, IID, IIE, IIF, IIG, IIIAB, IIICD, seen to fall and was picked up of all known meteorites. Stones ureilites, and winonaites. These IIIE, IIIF, IVA, IVB, and immediately after impact. Falls represent the crustal surface of other classes are very rare and ungrouped irons. are the most scientifically an asteroid and are divided into best collected after some Stony-irons comprise only 2 valuable meteorites since they two broad categories: chondrites experience in the study of percent of meteorites and are are pristine, unaltered samples and achondrites. Chondrites meteorites. divided into two categories: of extraterrestrial material. contain chondrules, which are Iron meteorites comprise 6 pallasites and mesosiderites. Finds are meteorites that were small spherical bodies formed by percent of the meteorites in Stony-irons contain pieces of an not seen to fall and are usually the re-melting of mineral grains museum collections. Irons are asteroid’s “stony” silicate mantle found accidentally. Finds have in the solar nebula. Chondrites pieces of the metallic core of an and its nickel-iron core. The been “terrestrialized”— are subdivided into ordinary asteroid. Iron meteorites are origin of pallasites is controver- weathered and chemically chondrites and enstatite chon- divided into three broad catego- sial: they were once widely altered—after being on Earth for drites, and can be further ries based on their nickel content: thought to represent the core- an extended period of time. subdivided into three basic types: octahedrites, hexahedrites and mantle boundary of an asteroid, Finds will exhibit weathered H (high-iron), L (low-iron), and ataxites. Hexahedrites contain but now seem more likely to fusion crust, which will not be as LL (low-low-iron). This letter the least nickel, 4.5 to 5.8 result from large impacts in the jet-black as the crust on a fall. designation is followed by a percent; octahedrites contain 4.5 early Solar System. Pallasites are Make sure the fusion crust is number, usually from 3 to 6. A to 6.5 percent nickel; and ataxites arguably the most beautiful still visible and not totally meteorite with well-defined, have the greatest nickel content, meteorites, containing gem-grade weathered away: the presence of unaltered chondrules is a 3; one 16 to 30 percent. Octahedrites olivine (peridot) in a nickel-iron fusion crust on a meteorite adds Figure 1: The three basic types of meteorites—stones, irons, and stony-irons. Left: Parnallee LL3 chondrite, which fell in the Madura district, Tamil Nadu, India, on February 28, 1857. Note the exquisite preservation of the chondrules, which were formed during the condensation of the solar nebula. Specimen is a partial slice weighting 5.5 grams and measuring 42 mm x 26 mm x 3 mm. Center: The Odessa IA coarse iron octahedrite was found in 1922 in Ector County, Texas. Note the Widmanstätten pattern typical of octahedrites. Specimen is an endpiece weighing 192.9 grams and measuring 65 mm x 60 mm x 15 mm. Rght: Stony-iron pallasites consist of gem-grade peridot (olivine) in a nickel-iron matrix and are the most stunningly beautiful of all the meteorites. Pictured is the Imilac pallasite found in 1822 in the Atacama Desert, Chile. Specimen is a partial slice weighting 64.4 grams and measuring 84 mm x 58 mm x 3 mm. 16 REFLECTOR ✶ D ECEMBER 2016 The aesthetics of a meteorite is Association). The IMCA ensures also a consideration when that members are experienced purchasing a meteorite. A full meteorite dealers and sell only slice of a stone, iron, or stony- authentic meteorites. iron is preferable to a partial Ensure that the meteorite market value to the specimen. mass of the specimen to obtain slice. Does the partial slice have comes with proper documenta- Meteorites are named after the the cost per gram. For example, a a natural edge with fusion crust? I tion. An undocumented meteorite locality from which they were $50 specimen weighing 10 grams personally do not like a perfectly is almost worthless to a collector! collected. The Meteoritical costs $5 per gram. Shop around, square or rectangular sliced All you know is that it is some Society has a nomenclature since dealer prices per gram of a meteorite. This particular cut type of stone or iron. But from committee, which assigns every meteoritic specimen can vary looks very synthetic and unap- where? What is the locality? What authenticated meteorite an tremendously. Ordinary chon- pealing to me. Iron meteorites is its classification? Is it a fall or official name (Table 1). drites typically average from $1 typically exhibit regmaglypts— a find? What is the official name? Meteorites are sold as to $5 up to $10 per gram. Falls depressions that look like Proper labeling is therefore individuals, endpieces, and slices. typically cost more than finds thumbprints—on their crusts, essential. When purchasing a An individual is a complete, uncut since fallen meteorites are in which adds aesthetic appeal. meteorite look for the specimen’s meteorite. An endpiece is an more pristine condition. Irons are Regmaglypts are the result of official name, classification, fall individual that has been cut in less expensive, typically averag- ablation from atmospheric entry. or find, fusion crust present, total half or in quarters. A slice is a ing $0.10 to $0.50 up to several Dealers will charge more for a known weight, cost per gram, cross-section of an individual. dollars per gram for individuals. meteorite that is aesthetically surface area (size), rarity, and Slices can be further cut in half Slices are typically priced at $1 pleasing. Most of the time, this is overall aesthetic appeal of the or in quarters and are then or more per gram. Pallasites are well worth the money. meteorite. A detailed label will referred to as partial slices. A pricey, up to $30 per gram. Table 1 lists several websites always be provided with a thinly cut slice will have a larger Mesosiderites are more afford- that are invaluable to the meteorite sold from an IMCA surface area than a thick slice of able at $5 to $10 per gram. meteorite collector. When member. the same weight or mass, and Lunar and martian meteorites are purchasing a meteorite, the buyer Recent finds in the Sahara therefore a thin slice will give you typically priced at several should be aware of some basics. Desert in Africa have flooded the the largest size for your money. thousand dollars per gram! I The online auction site eBay is a meteorite market. This is a good The total known weight is also would stay away from the rarer good place to start. When thing, since most of these a consideration when purchasing types of meteorites when first deciding to purchase a meteorite, meteorites are rather affordable a meteorite, because the total starting out. Once a collector has make sure the dealer is a for many people. Referred to as known weight will affect a obtained the more commonly member of the IMCA (Interna- NWA (northwest Africa) followed meteorite’s price. For example, available specimens and is more tional Meteorite Collectors by a number, they have been was there only a single stone that knowledgeable in the field of fell, or many individuals? Do the meteoritics, then it’s time to known individuals total only a few acquire the rarer specimens. As a pounds or kilograms, or over a collectable, meteorites appreciate ton? For example, the martian in value over time. However, meteorite Zagami fell on October conventional holdings like stocks, 3, 1962, in Nigeria. Only a single bonds, and mutual funds are stone weighing 40 pounds (18 kg) probably a much better long-term exists on the entire planet Earth! investment strategy.