{"product_id":"canyon-diablo-iron-meteorite-full-slice-iab-mg-112-54g-etched-both-sides-neumann-bands","title":"Canyon Diablo Iron Meteorite Full Slice, IAB-MG, 112.54g, Etched Both Sides, Neumann Bands","description":"\u003ch2\u003eFull slice from the iron that made Meteor Crater\u003c\/h2\u003e\n\u003cp\u003eThis 112.54 g full slice of Canyon Diablo is polished and etched on both faces. Bright kamacite plates cross one another over the whole surface, and scattered through them are dozens of elongated bronze-colored inclusions lined up with the plates. In the darker grains, fine Neumann bands cross one another in sets.\u003c\/p\u003e\n\u003cp\u003eCanyon Diablo is the iron meteorite recovered around Meteor Crater in northern Arizona. The Meteoritical Bulletin records it as a find, first described in 1891, and classifies it as Iron, IAB-MG.\u003c\/p\u003e\n\u003ch2\u003eStructure and features\u003c\/h2\u003e\n\u003cp\u003eBoth faces show the same coarse crossing plate structure. Long kamacite plates run in several directions and meet at angles, and areas of differently oriented metal catch the light in different tones of gray as the slice is turned. Buchwald (1975) records a kamacite bandwidth of 2.0 plus or minus 0.5 mm for Canyon Diablo, which places it among the coarse octahedrites.\u003c\/p\u003e\n\u003cp\u003eThe inclusions are the standout feature. They appear as many small, elongated bronze bodies, most of them a few millimeters long, aligned with the kamacite plates and repeated across both faces. They have not been analyzed. Buchwald describes cohenite, an iron nickel carbide, in Canyon Diablo as rounded crystals about 3 by 0.5 mm precipitated within the kamacite plates, which matches what these inclusions look like, so cohenite is the most likely identity, but it is not confirmed for this specimen. One larger, darker elongated body sits near one edge of the second face; it has also not been analyzed.\u003c\/p\u003e\n\u003cp\u003eThe close-up photographs show Neumann bands as fine straight lines crossing the darker grains, with several sets intersecting in places. Thin dark lines also trace some of the grain boundaries.\u003c\/p\u003e\n\u003cp\u003eThis is a full slice, so the natural exterior of the meteorite runs all the way around the edge, with brown terrestrial oxide from its long exposure in the ground. The slice has been professionally stabilized by Brian McDonald of Treasure Coast Meteorite Co., and both faces carry a protective coat of Renaissance Wax.\u003c\/p\u003e\n\u003cp\u003eThe display stand and scale cube in the photographs are not included.\u003c\/p\u003e\n\u003ch2\u003eDiscovery and provenance\u003c\/h2\u003e\n\u003cp\u003eThe site was known long before the meteorites were described. According to Buchwald (1975), people lived near the crater in precolumbian times, and the remains of twelfth century pit dwellings have been reported on the outer south slope of the rim. Buchwald adds that it is quite unlikely anyone witnessed the impact itself. Pioneers and prospectors knew the area in the 1840s to 1860s, and army scouts called it Franklin's Hole in 1871; it was later known as Coon Mountain or Coon Butte.\u003c\/p\u003e\n\u003cp\u003eThe first thorough description came in 1891 from the geologist and mineral dealer A. E. Foote, who named the irons after Canyon Diablo, a deep canyon about 5 km west of the crater, and the railway post office of the same name. Foote could find no lava or other volcanic rock at the crater and could not explain how it formed. In the same paper, Professor Koenig reported small diamonds in the iron, a finding later confirmed by other researchers.\u003c\/p\u003e\n\u003cp\u003eIn 1903 a group led by the lawyer and mining engineer D. M. Barringer staked a claim to the crater and began drilling for a large iron mass they believed lay buried beneath the floor, at a time when leading geologists still doubted an impact origin. The work continued until Barringer died in 1929. Buchwald notes that whether the main mass was ever struck remained disputed. The impact origin of the crater was settled decisively in 1960, when Chao, Shoemaker and Madsen identified coesite, a high pressure form of silica, in the crushed sandstone of the crater. The crater is also known as Barringer Crater, and Buchwald recorded that it was owned by the Barringer family.\u003c\/p\u003e\n\u003cp\u003eBuchwald estimated that more than 20,000 fragments, from 50 g to 639 kg, had been recovered from a roughly circular area about 15 km across centered on the crater. The Meteoritical Bulletin records a total mass of 30 t, matching the estimate of all recovered metallic specimens that Buchwald cites from Nininger (1949). Iron masses found hundreds of kilometers away, including Fair Oaks, Bloody Basin and Panamint Range, are listed in the Bulletin as synonyms and are thought to be fragments carried away from the crater area.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eSources: Buchwald (1975), \u003ca href=\"https:\/\/evols.library.manoa.hawaii.edu\/handle\/10524\/35665\" rel=\"noopener\" target=\"_blank\"\u003eHandbook of Iron Meteorites, volume 2, pages 381 and following\u003c\/a\u003e; Chao, Shoemaker and Madsen (1960), cited below; the \u003ca href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.cfm?code=5257\" rel=\"noopener\" target=\"_blank\"\u003eMeteoritical Bulletin entry\u003c\/a\u003e.\u003c\/em\u003e\u003c\/p\u003e\n\u003ch2\u003eScientific context\u003c\/h2\u003e\n\u003cp\u003eThe Meteoritical Bulletin classifies Canyon Diablo as Iron, IAB-MG. MG stands for main group: Canyon Diablo belongs to the main group of the IAB complex, a grouping assigned from trace element chemistry and nickel content rather than from etched structure. Buchwald reported 7.10% nickel, 0.46% cobalt, 80 ppm gallium, 320 ppm germanium and 1.9 ppm iridium, with about 1% carbon and 1% sulfur.\u003c\/p\u003e\n\u003cp\u003eMany IAB irons carry inclusions of graphite, troilite and carbides, and Canyon Diablo is a well studied example. Buchwald describes troilite and graphite nodules rimmed with schreibersite and cohenite, as well as the separate cohenite crystals within the kamacite plates of the kind most likely seen in this slice.\u003c\/p\u003e\n\u003cp\u003eNeumann bands are thin mechanical twins in kamacite, the low nickel iron phase, produced when a shock wave passes through the metal. After etching they show as sets of fine straight lines crossing the kamacite, and each set follows a different crystal plane. For more on the crossing plate structure, see \u003ca href=\"\/pages\/widmanstatten-pattern-explained\"\u003eWidmanstatten Pattern Explained\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eWhat the research reports\u003c\/h2\u003e\n\u003cp\u003eThe Meteoritical Bulletin lists this meteorite as Canyon Diablo, classified Iron, IAB-MG, found in 1891 in the United States with a recorded mass of 30 t. It was published in the Meteoritical Bulletin (MB 33, 1965), and its classification history runs from Iron (MB 33, 1965) to IAB (NHM Catalogue, 2000) to IAB-MG (MetBase, 2006). The Bulletin records no structural class, and the crater age given below comes from later work that replaced Buchwald's estimate. Findings come from the authors' own samples and methods and are given as the studies state them.\u003c\/p\u003e\n\u003ch3\u003eBuchwald (1975): the iron itself\u003c\/h3\u003e\n\u003cp\u003eVagn F. Buchwald's \u003ca href=\"https:\/\/evols.library.manoa.hawaii.edu\/handle\/10524\/35665\" rel=\"noopener\" target=\"_blank\"\u003eHandbook of Iron Meteorites\u003c\/a\u003e (University of California Press, 1975, volume 2, pages 381 and following), linked from the Bulletin entry, classifies Canyon Diablo as a coarse octahedrite (Og) with a bandwidth of 2.0 plus or minus 0.5 mm. He found Neumann bands and a range of shock structures, and showed that specimens from the crater rim had been reheated during the impact while many others were not. He describes cohenite as common, both as rims around troilite and schreibersite nodules and as rounded crystals in the Widmanstatten kamacite. Buchwald gave the best estimate of the crater's age at the time as 20,000 years, based on erosion and geological features; later dating replaced that figure.\u003c\/p\u003e\n\u003ch3\u003eChao, Shoemaker and Madsen (1960): proof of impact\u003c\/h3\u003e\n\u003cp\u003eE. C. T. Chao, E. M. Shoemaker and B. M. Madsen published \u003ca href=\"https:\/\/doi.org\/10.1126\/science.132.3421.220\" rel=\"noopener\" target=\"_blank\"\u003eFirst natural occurrence of coesite\u003c\/a\u003e (Science, volume 132, pages 220 to 222, 1960). Coesite had previously been known only from the laboratory. Finding it in sheared Coconino sandstone at Meteor Crater showed that the rock had been subjected to pressures far beyond anything a volcanic explosion produces, and gave geologists a mineral marker for recognizing impact craters elsewhere.\u003c\/p\u003e\n\u003ch3\u003ePhillips et al. (1991) and Nishiizumi et al. (1991): the age of the crater\u003c\/h3\u003e\n\u003cp\u003eTwo studies published together in Geochimica et Cosmochimica Acta, volume 55 (1991), dated the crater using isotopes produced by cosmic rays in rock exposed by the impact. F. M. Phillips and colleagues, in \u003ca href=\"https:\/\/doi.org\/10.1016\/0016-7037(91)90387-K\" rel=\"noopener\" target=\"_blank\"\u003eAge and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36Cl and 14C in rock varnish\u003c\/a\u003e (pages 2695 to 2698), measured chlorine-36 in boulders thrown out of the crater and reported a mean age of 49,700 plus or minus 850 years, consistent with earlier thermoluminescence dating. K. Nishiizumi and colleagues, in \u003ca href=\"https:\/\/doi.org\/10.1016\/0016-7037(91)90388-L\" rel=\"noopener\" target=\"_blank\"\u003eIn situ 10Be-26Al exposure ages at Meteor Crater, Arizona\u003c\/a\u003e (pages 2699 to 2703), reported a lower limit of 49,200 plus or minus 1,700 years. Together they place the impact roughly 50,000 years ago.\u003c\/p\u003e\n\u003ch3\u003eWhy this listing calls Canyon Diablo a coarse octahedrite\u003c\/h3\u003e\n\u003cp\u003eThe Meteoritical Bulletin Database records iron meteorites by chemical group only, so its entry for Canyon Diablo reads Iron, IAB-MG, with no structural class. The structural class used here comes from Buchwald (1975), cited above, which the Bulletin entry links directly.\u003c\/p\u003e\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eIs this meteorite authenticated?\u003c\/strong\u003e\u003cbr\u003eCanyon Diablo is classified in the Meteoritical Bulletin Database as Iron, IAB-MG, and the entry is linked at the end of this listing. Treasure Coast Meteorite Co. is IMCA member #3323. This specimen includes a certificate of authenticity documenting its weight, classification, and provenance.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs Canyon Diablo a fall or a find?\u003c\/strong\u003e\u003cbr\u003eA find. The Meteoritical Bulletin records it as found in 1891, with no observed fall. Dating of the crater places the impact roughly 50,000 years ago.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat are the bronze inclusions?\u003c\/strong\u003e\u003cbr\u003eThey have not been analyzed. Their shape, color and alignment with the kamacite plates match Buchwald's (1975) description of cohenite, an iron nickel carbide that is common in Canyon Diablo, so cohenite is the most likely identity, but it is not confirmed for this specimen.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does full slice mean?\u003c\/strong\u003e\u003cbr\u003eThe slice was cut all the way across the original mass, so the natural exterior edge of the meteorite runs around the entire outline. Both faces have been polished and etched.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat are Neumann bands?\u003c\/strong\u003e\u003cbr\u003eNeumann bands are shock deformation features in kamacite. When a shock wave passes through the metal, the crystal lattice twins along specific planes, and after etching these twins show as fine parallel lines within individual kamacite crystals.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHas this iron been stabilized?\u003c\/strong\u003e\u003cbr\u003eYes. This slice was professionally stabilized by Brian McDonald of Treasure Coast Meteorite Co. before listing, as every iron meteorite we sell now is, to help guard against the rust that can develop in iron meteorites over time. Both faces were then coated with Renaissance Wax.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is included with this specimen?\u003c\/strong\u003e\u003cbr\u003eThe 112.54 g slice as photographed and a certificate of authenticity. Display stands and scale cubes shown in the photographs are not included.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow should I store an etched iron meteorite?\u003c\/strong\u003e\u003cbr\u003eKeep it in a low humidity environment. Etched surfaces react to moisture more readily than natural surfaces, so a silica gel pack in the storage container helps prevent oxidation. Because this specimen has been professionally stabilized and coated with Renaissance Wax, no oil is needed. Handle it with gloves or clean, dry hands.\u003c\/p\u003e\n\u003ch2\u003eCollector significance\u003c\/h2\u003e\n\u003cp\u003eCanyon Diablo is the meteorite behind Meteor Crater, the crater that helped prove impacts shape planetary surfaces. Most Canyon Diablo on the market is sold as small uncut individuals. This full slice is etched on both faces, keeps the natural edge all the way around, and shows a dense field of bronze inclusions and Neumann bands that are visible without magnification.\u003c\/p\u003e\n\u003cp\u003eFor more iron meteorites, see our full \u003ca href=\"\/collections\/iron-meteorites\"\u003eIron Meteorites\u003c\/a\u003e collection.\u003c\/p\u003e\n\u003cp\u003eMeteoritical Bulletin entry: \u003ca href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.cfm?code=5257\" rel=\"noopener\" target=\"_blank\"\u003eCanyon Diablo\u003c\/a\u003e | Classification: Iron, IAB-MG | Find, United States, 1891 | Treasure Coast Meteorite Co., IMCA #3323\u003c\/p\u003e","brand":"Treasure Coast Meteorite Co.","offers":[{"title":"Default Title","offer_id":47012046635055,"sku":"CANYON-DIABLO-112.54G-FULLSLICE-NEUMANN","price":450.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0726\/9724\/9839\/files\/canyon-diablo-iron-iab-mg-112.54g-full-slice-01-etched-face-stand.jpg?v=1792366714","url":"https:\/\/www.tcmeteorites.com\/products\/canyon-diablo-iron-meteorite-full-slice-iab-mg-112-54g-etched-both-sides-neumann-bands","provider":"Treasure Coast Meteorite Co.","version":"1.0","type":"link"}