{"product_id":"nwa-18591-diogenite-43-13g-end-cut","title":"NWA 18591 Diogenite Meteorite, 43.13g End Cut, HED Achondrite, Olivine-Bearing from Vesta","description":"\u003ch2\u003eA 43.13 gram olivine-bearing diogenite end cut from asteroid Vesta\u003c\/h2\u003e\u003cp\u003eThis is a 43.13 g end cut of NWA 18591, a diogenite classified as an olivine-bearing HED achondrite from asteroid 4 Vesta. Diogenites formed deep in Vesta's crust, where minerals settled out of slowly cooling magma, so they are coarser and more orthopyroxene-rich than the basaltic eucrites from the surface. The polished cut face shows the brecciated interior of the meteorite: dark orthopyroxene clasts set in a fragmental matrix, with the tan tones of moderate desert weathering across the surface. For background on the type, see our guide on \u003ca href=\"https:\/\/www.tcmeteorites.com\/pages\/what-is-an-achondrite\"\u003ewhat an achondrite is\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eStructure and features of this end cut\u003c\/h2\u003e\u003cp\u003eThe polished cut face reveals a breccia built from millimeter to centimeter sized clasts of orthopyroxene set within a finer fragmental matrix, the record of impact processing on Vesta's surface. Under close light the pyroxene clasts read as dark green to near black, threaded with fine fracture networks, while the surrounding matrix carries the orange and tan coloring of moderate terrestrial weathering. Scattered olivine accompanies the orthopyroxene, which is why the meteorite carries the olivine-bearing designation, and accessory chromite, iron metal, and troilite are present in the rock. As an end cut, the piece keeps the outer surface of the stone on its back side: a rough, brown weathered exterior with dark pyroxene showing through and patches of pale weathering deposits, which shows how the meteorite looked before it was cut. It is photographed alongside a one centimeter scale cube.\u003c\/p\u003e\n\u003ch2\u003eDiscovery and provenance\u003c\/h2\u003e\n\u003cp\u003eNWA 18591 was found in northwest Africa in 2024 as seven stones with weathered fusion crust, for a total known weight of approximately 610 grams. The stones were acquired from a dealer in Morocco, and the main mass is held by Treasure Coast Meteorite Co. The meteorite was classified by D. Sheikh at the Cascadia Meteorite Laboratory at Portland State University, where a 22.8 gram type specimen is on deposit, and the name was approved by the Meteoritical Society in 2026. This end cut therefore comes directly from the holder of the main mass, with provenance that traces to the classifying laboratory. Browse related specimens in our \u003ca href=\"https:\/\/www.tcmeteorites.com\/collections\/diogenites\"\u003eDiogenites collection\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch2\u003eScientific context\u003c\/h2\u003e\n\u003cp\u003eDiogenites are orthopyroxenite achondrites from the deep crust of asteroid 4 Vesta, part of the howardite, eucrite, and diogenite family whose common origin is confirmed by oxygen isotopes, pyroxene chemistry, and the reflectance spectra measured directly at Vesta by NASA's Dawn mission. In NWA 18591 the low-calcium pyroxene has a ferrosilite content of Fs27.8 with a magnesium number of about 72, and the accompanying olivine sits at Fa27.0, values consistent with an olivine-bearing diogenite. The rock records a moderate shock stage, evidence of the impact history that brecciated Vesta's crust and eventually launched this material toward Earth. The classification is published in the \u003ca rel=\"noopener\" href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.cfm?code=87167\" target=\"_blank\"\u003eMeteoritical Bulletin, No. 115\u003c\/a\u003e. You can read more about how meteorites earn an official record on our \u003ca href=\"https:\/\/www.tcmeteorites.com\/pages\/meteoritical-bulletin-explained\"\u003eMeteoritical Bulletin explained\u003c\/a\u003e page.\u003c\/p\u003e\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eIs this meteorite authenticated?\u003c\/strong\u003e\u003cbr\u003eYes. NWA 18591 is an officially classified diogenite recorded in the Meteoritical Bulletin, No. 115, with its main mass held by Treasure Coast Meteorite Co. This end cut ships with a Treasure Coast Meteorite Co. certificate of authenticity and is offered by Treasure Coast Meteorite Co., IMCA member #3323.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is a diogenite?\u003c\/strong\u003e\u003cbr\u003eA diogenite is an orthopyroxene-rich achondrite from the deep crust of asteroid 4 Vesta, coarser grained than the basaltic eucrites that formed at the surface of the same body. Learn more on our \u003ca href=\"https:\/\/www.tcmeteorites.com\/collections\/diogenites\"\u003eDiogenites collection\u003c\/a\u003e page.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat does olivine-bearing mean here?\u003c\/strong\u003e\u003cbr\u003eThe classification notes that this diogenite contains olivine alongside its dominant orthopyroxene. Olivine-bearing diogenites sample slightly different levels of Vesta's cumulate pile than orthopyroxene-only diogenites.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is an end cut?\u003c\/strong\u003e\u003cbr\u003eAn end cut is the piece left at the end of a stone after slicing. It has one flat polished cut face showing the interior and keeps the original weathered exterior on the other side, so you can see both the inside and the outside of the meteorite in one specimen.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is included?\u003c\/strong\u003e\u003cbr\u003eThe 43.13 g end cut shown, with a Treasure Coast Meteorite Co. certificate of authenticity.\u003c\/p\u003e\n\u003ch2\u003eCollector significance\u003c\/h2\u003e\n\u003cp\u003eAn end cut of a classified diogenite whose main mass is held in house is a strong provenance piece, tying the specimen directly to the meteorite's holder and to the Cascadia Meteorite Laboratory that classified it. The brecciated orthopyroxene texture and the olivine-bearing chemistry make this a representative sample of Vesta's deep crust, a good anchor for an HED suite alongside eucrites and howardites. Full classification data, chemistry, and provenance are published in the \u003ca rel=\"noopener\" href=\"https:\/\/www.lpi.usra.edu\/meteor\/metbull.cfm?code=87167\" target=\"_blank\"\u003eMeteoritical Bulletin entry for NWA 18591\u003c\/a\u003e.\u003c\/p\u003e","brand":"Treasure Coast Meteorite Co.","offers":[{"title":"Default Title","offer_id":47129590169647,"sku":"NWA-18591-43.13G-END-CUT","price":787.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0726\/9724\/9839\/files\/nwa-18591-diogenite-43.13g-end-cut-01-cut-face-scale-cube.jpg?v=1793839705","url":"https:\/\/www.tcmeteorites.com\/products\/nwa-18591-diogenite-43-13g-end-cut","provider":"Treasure Coast Meteorite Co.","version":"1.0","type":"link"}