{"title":"Diogenites","description":"\u003cp\u003eDiogenites are orthopyroxenite achondrites from the deep crust or upper mantle of asteroid 4 Vesta. They represent material that crystallized more slowly and at greater depth than eucrites, giving them a coarser grain size and a composition dominated by the mineral orthopyroxene. Unless specifically stated in the listing, specimens in this collection are Meteoritical Bulletin classified.\u003c\/p\u003e\n\n\u003ch2\u003eHow we verify diogenites are real\u003c\/h2\u003e\n\u003cp\u003eEvery specimen is tied to a Meteoritical Bulletin entry, the official global registry of classified meteorites maintained by the Meteoritical Society. Vesta origin is confirmed through oxygen isotope ratios, pyroxene chemistry, and reflectance spectra that match measurements made directly at Vesta by NASA's Dawn mission from 2011 to 2012. The Bulletin record is the definitive proof of authenticity. Read more: \u003ca href=\"\/pages\/meteoritical-bulletin-explained\"\u003eThe Meteoritical Bulletin Explained\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eFrom deep within Vesta\u003c\/h2\u003e\n\u003cp\u003eWhile eucrites represent Vesta's basaltic surface, diogenites sample deeper levels, the cumulate rocks that formed as minerals settled out of slowly cooling magma bodies at depth within the crust. The result is a coarser-grained, orthopyroxene-dominated rock quite different in appearance from the finer-grained eucrites despite originating from the same parent body.\u003c\/p\u003e\n\u003cp\u003eDiogenites are named after the ancient Greek philosopher Diogenes of Apollonia, who proposed in the 5th century BC that meteorites came from space, a remarkably prescient idea for its time.\u003c\/p\u003e\n\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eHow do diogenites differ from eucrites?\u003c\/strong\u003e Eucrites are basaltic surface rocks dominated by pyroxene and plagioclase. Diogenites are coarser-grained cumulate rocks from deeper in Vesta's crust, dominated by orthopyroxene with little or no plagioclase. They are visually distinct, with diogenites often having a granular, greenish-gray appearance. Read more: \u003ca href=\"\/collections\/eucrites\"\u003eEucrites\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre diogenites magnetic?\u003c\/strong\u003e Diogenites contain very little metallic iron and are typically not noticeably magnetic. A strongly magnetic specimen marketed as a diogenite warrants closer inspection. Read more: \u003ca href=\"\/pages\/are-meteorites-magnetic\"\u003eAre Meteorites Magnetic?\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow can I tell a diogenite is real?\u003c\/strong\u003e Authentic diogenites have a Meteoritical Bulletin entry, ship with documentation, and show characteristic coarse orthopyroxene texture. Many diogenites are brecciated by impacts on Vesta. Read more: \u003ca href=\"\/pages\/how-can-you-tell-if-a-meteorite-is-real\"\u003eHow Can You Tell if a Meteorite Is Real?\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does the name diogenite mean?\u003c\/strong\u003e The group is named after Diogenes of Apollonia, the ancient Greek philosopher who suggested that meteorites had an extraterrestrial origin. The type specimen, the Tatahouine fall, helped formalize the group in 1931.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre these specimens authenticated?\u003c\/strong\u003e Unless otherwise noted, every diogenite here has a Meteoritical Bulletin record and ships with a Treasure Coast Meteorite Co. certificate of authenticity.\u003c\/p\u003e\n\n\u003cp\u003eSee also: \u003ca href=\"\/collections\/eucrites\"\u003eEucrites\u003c\/a\u003e · \u003ca href=\"\/collections\/howardites\"\u003eHowardites\u003c\/a\u003e · \u003ca href=\"\/collections\/hed-meteorites\"\u003eHED Meteorites\u003c\/a\u003e · \u003ca href=\"\/collections\/stony-meteorites\"\u003eStony Meteorites\u003c\/a\u003e · \u003ca href=\"\/pages\/what-is-an-achondrite\"\u003eWhat Is an Achondrite?\u003c\/a\u003e · \u003ca href=\"\/pages\/are-meteorites-illegal-to-own\"\u003eAre Meteorites Illegal to Own?\u003c\/a\u003e\u003c\/p\u003e","products":[{"product_id":"nwa-17918-diogenite-pm-polymict-breccia-from-vesta-hed-13-33g-polished-end-cut","title":"NWA 17918 Diogenite-pm Meteorite End Cut, 13.33g, Polished Breccia Texture from Vesta","description":"\u003ch2\u003ePolished window into Vesta's deep crust\u003c\/h2\u003e\u003cp\u003eThis 13.33g polished end cut reveals the complex internal architecture of a polymict diogenite breccia. The mirror-polished surface exposes distinct orthopyroxene-rich clasts set within a matrix of comminuted impact debris, documenting multiple collision events on asteroid Vesta's surface. The cut preserves sharp boundaries between individual fragments, each representing different zones within the asteroid's lower crust or upper mantle. Polishing brings out subtle color variations between clast types and highlights the three-dimensional structure of this impact-assembled rock.\u003c\/p\u003e\u003cp\u003eThe specimen's form as an end cut provides both a display face showing the full brecciated texture and a natural exterior surface on the opposite side. At 13.33g, this piece offers substantial mass for a diogenite sample while maintaining excellent visual clarity of the polymict structure. The polish reveals grain boundaries and crystal orientations within individual pyroxene fragments.\u003c\/p\u003e\u003ch2\u003eOrthopyroxene clasts and impact assembly\u003c\/h2\u003e\u003cp\u003eThe dominant mineral phase visible throughout this section is orthopyroxene, the defining component of diogenitic material. Individual clasts range from millimeter-scale fragments to larger domains spanning several millimeters, each showing the characteristic greenish-gray coloration of magnesium-rich pyroxene. These fragments originated as crystallized magma deep within Vesta's interior, later excavated and mixed through violent impact gardening of the asteroid's surface.\u003c\/p\u003e\u003cp\u003eThe polymict nature becomes evident in the varying crystal sizes and textures between adjacent clasts. Some fragments preserve coarse-grained plutonic textures from slow cooling at depth, while others show finer crystallization patterns. The matrix binding these fragments consists of crushed diogenitic material, lithified through impact compression and heating. This assemblage records the cumulative effect of countless impacts that have processed and reprocessed Vesta's crustal material over 4.5 billion years.\u003c\/p\u003e\u003ch2\u003eScientific context\u003c\/h2\u003e\u003cp\u003eDiogenites represent the deepest crustal samples from asteroid 4 Vesta, the second-largest body in the main asteroid belt. These rocks crystallized from magma chambers several kilometers beneath Vesta's surface during the asteroid's early differentiation. The Dawn spacecraft mission confirmed the connection between HED meteorites and Vesta through spectroscopic mapping and geochemical analysis, making diogenites among the few meteorite types with a confirmed parent body.\u003c\/p\u003e\u003cp\u003eThe polymict classification indicates this specimen formed through impact brecciation on Vesta's surface, where collisions mixed fragments from different depths and locations within the diogenitic crust. NWA 17918 was classified in 2025, making it one of the most recently recognized members of the diogenite group. Study of such specimens helps planetary scientists understand the internal structure of differentiated asteroids and the processes that have modified their surfaces over billions of years. For broader context on meteorite identification and classification, see our guide on \u003ca href=\"\/blogs\/meteorite-guides\/how-to-tell-if-a-rock-is-a-meteorite\"\u003eHow to Tell if a Rock is a Meteorite\u003c\/a\u003e.\u003c\/p\u003e\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eIs this meteorite authenticated?\u003c\/strong\u003e Yes, NWA 17918 is officially classified as diogenite-pm by the Meteoritical Society. You can verify this classification through the Meteoritical Bulletin entry: \u003ca href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.php?sea=NWA%2017918\u0026amp;sfor=names\" target=\"_blank\" rel=\"noopener\"\u003eNWA 17918\u003c\/a\u003e. This specimen includes a certificate of authenticity documenting its classification and provenance.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat does polymict (pm) mean?\u003c\/strong\u003e Polymict refers to a breccia containing fragments from multiple source rocks or locations. In this diogenite, polymict texture indicates that impacts on Vesta's surface mixed clasts from different depths or regions within the diogenitic crust, then lithified them into a single rock. The \"pm\" designation distinguishes this from monomict diogenites, which contain fragments from a single source.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included with this specimen?\u003c\/strong\u003e You receive the 13.33g polished end cut and a certificate of authenticity. No display stand is included.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy is the HED-Vesta connection scientifically important?\u003c\/strong\u003e HED meteorites are the only achondrite group with a confirmed asteroidal parent body, verified by NASA's Dawn mission data. This connection allows scientists to study Vesta's geology through laboratory analysis of meteorites while comparing results to spacecraft observations, providing unique insights into asteroid differentiation and crustal evolution.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow should I display a polished end cut?\u003c\/strong\u003e The polished face shows the internal structure best when viewed flat or at a slight angle under good lighting. Many collectors use small acrylic easels or lean the specimen against a backdrop to showcase both the polished surface and the natural exterior edge.\u003c\/p\u003e\u003ch2\u003eCollector significance\u003c\/h2\u003e\u003cp\u003eDiogenite-pm specimens occupy a specialized niche in HED collecting, representing the deepest crustal material from Vesta available to private collectors. Only 74 meteorites carry the diogenite-pm classification, making this subtype substantially rarer than eucrites or howardites. The 13.33g mass provides sufficient size to appreciate the clast structure while remaining accessible compared to larger museum-grade pieces.\u003c\/p\u003e\u003cp\u003eThe 2025 classification date places NWA 17918 among the newest diogenite additions to the Meteoritical Bulletin, offering collectors an opportunity to acquire recently classified material. The polished preparation reveals structural details invisible on uncut specimens, making this format particularly valuable for collectors focused on understanding impact processes and asteroid geology. This specimen fits well in collections emphasizing \u003ca href=\"\/collections\/diogenites\"\u003eDiogenites\u003c\/a\u003e or broader \u003ca href=\"\/collections\/hed-meteorites\"\u003eHED Meteorites\u003c\/a\u003e representing all three components of Vesta's differentiated crust.\u003c\/p\u003e\u003cp\u003eMeteoritical Bulletin entry: \u003ca href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.php?sea=NWA%2017918\u0026amp;sfor=names\" target=\"_blank\" rel=\"noopener\"\u003eNWA 17918\u003c\/a\u003e | Classification: Diogenite-pm | Find, Algeria, 2025\u003c\/p\u003e","brand":"Treasure Coast Meteorite Co.","offers":[{"title":"Default Title","offer_id":44796018360367,"sku":"NWA-17918-13.33G-ENDCUT","price":255.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0726\/9724\/9839\/files\/IMG_7216.heic?v=1766459540"},{"product_id":"nwa-17918-diogenite-pm-slice-9-29g-hed-1-of-74","title":"NWA 17918 Diogenite-pm Meteorite Slice, HED Achondrite, 9.29g, Polymict Breccia from Vesta","description":"\u003ch2\u003ePolymict diogenite from Vesta's lower crust\u003c\/h2\u003e\n\u003cp\u003eThis 9.29g slice of NWA 17918 displays the characteristic texture of a polymict diogenite, with multiple fragments of orthopyroxene-rich material embedded in a fine-grained matrix. The slice reveals distinct clast boundaries where different generations of plutonic rock meet, preserving a record of impact mixing in Vesta's lower crust. The specimen's cross-section shows the coarse crystalline structure typical of slowly cooled deep crustal material, with orthopyroxene crystals visible throughout the brecciated matrix.\u003c\/p\u003e\n\u003cp\u003eFound in Algeria in 2025, NWA 17918 joins a limited group of classified polymict diogenites. With only 76 total classifications recorded for this material, specimens remain scarce in both research and private collections. The slice format provides an optimal view of the internal structure, making the polymict nature of the breccia immediately apparent.\u003c\/p\u003e\n\u003ch2\u003eOrthopyroxene-dominated lithology\u003c\/h2\u003e\n\u003cp\u003eDiogenites consist primarily of orthopyroxene, a magnesium-iron silicate mineral that crystallized from magma deep within Vesta's crust. The polymict designation indicates this specimen contains fragments from multiple source regions, mixed together by ancient impacts. The varying grain sizes and textures within the slice reflect different cooling histories, with some clasts originating from deeper, more slowly cooled layers than others.\u003c\/p\u003e\n\u003cp\u003eThe coarse crystalline structure distinguishes diogenites from the finer-grained eucrites that formed closer to Vesta's surface. Under magnification, the orthopyroxene crystals show the blocky, prismatic forms characteristic of pyroxene minerals, with cleavage planes intersecting at roughly 90-degree angles. The darker matrix material between clasts represents impact-generated melt and crushed mineral grains.\u003c\/p\u003e\n\u003ch2\u003eDiscovery and provenance\u003c\/h2\u003e\n\u003cp\u003eNWA 17918 was recovered in 2025 from the Adrar region of Algeria, totaling 996.87 grams across six stones. The find joins the limited inventory of polymict diogenites available to researchers and collectors, with only a small number of classified specimens of this type circulating worldwide.\u003c\/p\u003e\n\u003cp\u003eClassification was performed by Jose Garcia of ADARA (Petrography and Curation of Astromaterials, Canary Islands, Spain). The type specimen of 20.30 grams is held by MUNA (Museo de la Naturaleza y Arqueologia, Tenerife, Spain), with two thin sections retained at ADARA. The main mass is held by Brian McDonald of Treasure Coast Meteorite Co. The classification was approved 21 December 2025 and published in Meteoritical Bulletin 114.\u003c\/p\u003e\n\u003cp\u003ePetrographic analysis confirmed the polymict diogenite designation based on the coexistence of diogenitic and eucritic pyroxene phases. The diogenitic fraction is dominated by low-calcium orthopyroxene (Fs 28.4 to 33.3, Wo 2.9 to 4.3) with pigeonite, subcalcic augite, and ferroan olivine clasts (Fa 65.5 to 70.9). The minor eucritic component includes low-calcium pyroxene (Fs 62.8), calcic plagioclase (An 83.2 to 85.0), and a silica polymorph. Accessory chromite and minor FeNi metal are also present, with magnetic susceptibility measured at 3.40.\u003c\/p\u003e\n\u003ch2\u003eScientific context: Vesta's differentiated interior\u003c\/h2\u003e\n\u003cp\u003eThe asteroid 4 Vesta is the parent body of the HED meteorite suite, which includes howardites, eucrites, and diogenites. Vesta is one of the few asteroids known to have undergone full planetary differentiation, developing a metallic core, a silicate mantle, and a crust. Diogenites originated in the deeper crustal layers, where slow cooling allowed orthopyroxene crystals to grow to substantial size before solidification.\u003c\/p\u003e\n\u003cp\u003eNASA's Dawn mission, which orbited Vesta from 2011 to 2012, confirmed the long-suspected link between HED meteorites and this differentiated asteroid. Spectral measurements from Dawn matched laboratory analyses of diogenites, eucrites, and howardites, providing direct evidence that these meteorites originated from Vesta's surface. The polymict diogenites in particular record the violent impact history that excavated and mixed material from various crustal depths.\u003c\/p\u003e\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eIs this meteorite authenticated?\u003c\/strong\u003e Yes. NWA 17918 is classified as Diogenite-pm in the Meteoritical Bulletin. The official classification record is publicly available through the Meteoritical Society database.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does \"polymict\" mean?\u003c\/strong\u003e Polymict refers to a breccia composed of multiple distinct rock types or fragments from different source regions, mixed together by impact processes. In this case, the slice contains both diogenitic and minor eucritic components.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhere does this meteorite come from?\u003c\/strong\u003e NWA 17918 originated on the asteroid 4 Vesta, the second-largest object in the asteroid belt. It was ejected by an impact and eventually fell to Earth, where it was recovered in the Adrar region of Algeria in 2025.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow is the slice prepared?\u003c\/strong\u003e The specimen was cut using a precision diamond saw and the cut surface was polished to reveal the internal structure. This preparation allows direct visual study of the orthopyroxene clasts and matrix relationships.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs shipping insured?\u003c\/strong\u003e Yes. All specimens ship fully insured with tracking. Treasure Coast Meteorite Co. handles each piece with care appropriate to its scientific and collector value.\u003c\/p\u003e\n\u003ch2\u003eCollector significance\u003c\/h2\u003e\n\u003cp\u003ePolymict diogenites represent a relatively scarce subset of the HED meteorite group, with only 76 approved classifications worldwide. The combination of multiple orthopyroxene generations, accessory chromite and FeNi metal, and the rare eucritic component makes specimens like NWA 17918 particularly valuable for collectors building a Vesta-focused reference collection. This 9.29g slice provides a substantial viewing area while remaining accessible to private collectors.\u003c\/p\u003e\n\u003cp\u003eThe slice format displays the polymict texture in a way that complete individuals cannot, with clast boundaries and grain relationships immediately visible. Explore additional Vesta-derived specimens in our \u003ca href=\"\/collections\/achondrites\"\u003eAchondrites\u003c\/a\u003e collection.\u003c\/p\u003e\n\u003cp\u003eMeteoritical Bulletin entry: \u003ca rel=\"noopener\" href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.cfm?code=86256\" target=\"_blank\"\u003eNorthwest Africa 17918\u003c\/a\u003e. 996.87 g | MB 114 (2025).\u003c\/p\u003e","brand":"Treasure Coast Meteorite Co.","offers":[{"title":"Default Title","offer_id":44902133956655,"sku":"NWA-17918-9.29G-SLICE","price":180.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0726\/9724\/9839\/files\/nwa-17918-diogenite-pm-meteorite-9.29g-front-face.heic?v=1779457546"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0726\/9724\/9839\/collections\/NWA-17918-diogenite-hed-achondrite-slice-polished.jpg?v=1776656773","url":"https:\/\/www.tcmeteorites.com\/collections\/diogenites.oembed","provider":"Treasure Coast Meteorite Co.","version":"1.0","type":"link"}