Though Dunnite was generally considered an insensitive substance, by 1911 the United States Army had abandoned its use in favor of other alternatives. Brucite is the mineral form of magnesium hydroxide, with the chemical formula Mg(OH) 2. Ocean Pictures, Moscow http://www.flickr.com/photos/rschott/4579356243/in/set-72157623033417595, http://ron.outcrop.org/images/IMG_1117.JPG. So we should expect to see lots of unusual mineral varieties in dunite. The forsterite-fayalite minerals also occur in dolomitic limestones, marbles, and metamorphosed iron-rich sediments. It usually crystallizes in the presence of plagioclase and pyroxene to form gabbro or basalt. Chemical Formula (Ca,Na)(Mg,Fe,Al)(Al,Si) 2 O 6: Composition: Silicate of calcium, sodium, magnesium, iron, and aluminum. Minerals & Varieties. I just take the samples out of plastic bags where they are stored, take photos of the best samples and quickly move on. Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed in 1906 by US Army Major Beverly W. Dunn, who later served as the chief inspector of the Bureau of Transportation Explosives. It was the first explosive used in an aerial bombing operation in military history, performed by Italian pilots in Libya in 1911. Rocks that contain more than 40% olivine are peridotites. Call for Submission of expression of interest for equipment and engineering service procurement : CLOSED Dunite, light yellowish green, intrusive igneous ultramafic rock that is composed almost entirely of olivine.Dunite usually forms sills (tabular bodies intruded between other rocks) but may also occur as lenses (thin-edged strata) or pipes (funnels, more or less oval in cross section, that become narrower with increasing depth).It is a common rock in Earth’s upper mantle. Chemical Name: CAS Number: 1344-59-8 . It was used extensively by the United States Navy during World War I. This rock usually contains chromite (Mg-bearing spinel group mineral). There’s almost certainly more than 10% chromian diopside (the bright green CPX) visible, IMHO. From James St. John . Representative chemical analyses of soda-tremolites in the Horokanai dunites are listed in Table 1. However, olivine readily alters and loses its bright green color pretty quickly. If you need a photo of a piece of true dunite I can offer this weathered example (with chromite seams): http://www.flickr.com/photos/rschott/4579356243/in/set-72157623033417595 and if you want a fresher example, how about: http://ron.outcrop.org/images/IMG_1117.JPG. This would involve the mining of dunite rocks in quarries followed by crushing and grinding as to create fine ground rock that would react with the atmospheric carbon dioxide. Emergency Phone Numbers: 1-630-252-6131 or 1-630-252-5731 . This rock belongs to my university. Peridotite that contains more than 90% olivine have a special name, they are called dunite (named in 1864 after Dun mountain in New Zealand). Olivine is used as a refractory material. I took that photo few days ago but I can not examine the sample at the moment. 6.11.1.1 Platiniferous Chromite and Nickel Sulfide. The crystal chemical formula is approximately as follows; (Na0.6) (Ca1.4Na0.6) (Mg4.6 Fe2+0.2Cr0.1Al0.1) (Al0.2Si7.8) O22(OH)2. Link to MinDat.org Location Data. U. S. Department of Energy . Dunite. These minerals are relatively… Read More But how does olivine used as refractory materials. Magnesium is a very common chemical element in the mantle. away few years before he passed away (I will write a post about him soon). Width of sample 8 cm. It was used extensively by the United States Navy during World War I.[5]. It is chemically related to the more stable explosive trinitrotoluene (TNT). Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. The resulting products are magnesite and silica which could be commercialized. A sample from Norway which is mined because of its high olivine content. It is chemically related to the more stable explosive trinitrotoluene (TNT). These types of rocks are most common at divergent plate boundaries and at hot spots within the centers of tectonic plates. Dunite (silicate magnesium) Dunite is a plutonic rock of ultramafic composition and is mainly characterized by coarse grained texture. In 2008 caches of discarded Dunnite in remote locations were mistaken for rusty rocks at Cape Porcupine, Newfoundland and Labrador, Canada.[7][8]. Its chemical classification is basic rock, having mainly magnesium bearing olivine (forstrite) as the principal mineral, with minor contents of pyroxene. However, if the most common spinel mineral is magnetite, dunite is named olivinite instead. Grooves on the outcrop of dunite is a result of rain-induced weathering. Minerals. Variable Formula (Ca,Na)(Mg,Fe,Al,Zn,Mn,Ti)(Al,Si) 2 O 6: Color: Green, grayish-green, greenish brown, dark brown, black: Streak: Light green to colorless: Hardness: 5 - 6: Crystal System Chemical Formula: (Ru,Os)As2 : Composition: Molecular Weight = 273.20 gm Arsenic 54.85 % As Osmium 17.41 % Os Ruthenium 27.75 % Ru _____ 100.00 % : Empirical Formula: Ru 0.75 Os 0.25 As 2: Environment: Occurs in a chromium deposit related to augite peridotite and dunite. Hence, many samples look dull yellow, not green anymore. Dunite. Most common mafic minerals in ultramafic rocks are definitely pyroxenes and olivine (if hornblende is present it is added to pyroxenes). Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene. The compositional Helgehornsvatnet, Norway. “Ultramafic” means that mafic minerals form more than 90% on the rocks composition. Dunite PM is an ultramaphic rock exploited in the north of Spain with a basic chemical classification being olivine and serpentine its principal minerals. The platiniferous sulfide zones are up to 15 m thick, and associated with magnetite and graphite-rich black dunite lenses. Dunite could be used to sequester CO2 and help mitigate global climate change via accelerated chemical rock weathering. Outcrop of dunite in Norway. Magnesite Magnesite is a mineral with the chemical formula MgCO3 (Magnesium Carbonate). Magnesium rich olivine forms a large part of the peridotite and therefore has a high magnesium content. Rather, the shell encasing it would penetrate the armor, after which the charge would be triggered by a base fuze. Wehrlite contains almost no orthopyroxene but is rich in clinopyroxene and olivine. i. 1.1 Formation. Dolomite is a common rock-forming mineral. Dunnite typically did not detonate on striking heavy armor. [6] The Navy, however, used it in armor-piercing artillery shells and projectiles, and in coastal defense. Harzburgite is rich in olivine and orthopyroxene but there can be only up to 5% clinopyroxene. Dunite, the parent rock of Magnesite contains 49% of MgO and 39% of SiO2 and the Magnesite is derived from the Dunite. Complete Information Guide to Rocks, Minerals, & Gemstones . [4] Streak is the color of rock when it is crushed or powdered. Please enlighten me on this. It can be formed in two ways. Dunite loses its green color rapidly when exposed to rain. However, its beauty is not the reason to reserve a separate rock name for it. Dunnite can be used as a precursor to the highly stable explosive TATB (1,3,5-triamino-2,4,6-trinitrobenzene), by first dehydrating it to form picramide (attaching the ammonia as an amine group instead of an ion) and then further aminating it. View All Minerals; View by Alphabetical Order Interesting. I am destined to make lots of mistakes but I hope that fellow geologists help when they spot possible errors. Haldar, in Platinum-Nickel-Chromium Deposits, 2017. Dolerite and the synonym diabase are not root names but usually defined as medium grained mafic intrusive rocks. CHEMICAL AND MODAL COMPOSITION OF DUNITE FROM DUN MOUNTAIN, NELSON By J. J. REED, Department of Scientific and Industrial Research, New Zealand Geological Survey, Lower Hutt (Received for publication, 15 June 1959) Summary A chemical and modal analysis is presented of the type dunite discovered by F. von Hochstetter on Dun Mountain, Nelson. These early formed peridot crystals can settle by gravity forming dunite, a rock composed essentially of olivine, or the rock known as peridotite which also contains pyroxene with occaisional accessories hornblende, ilmenite, garnet, hematite or chromite. I already mentioned chromite, but Mg-bearing garnet pyrope is quite common as well. There are many wonderful samples but unfortunately they are mostly poorly described or not at all. Im interested in ultarabasic rocks specially dunite bearing chromite,your samples very nice. (1998) Minerals First discovered on the territory of the former Soviet Union 369p. SECTION 1: CHEMICAL PRODUCTS & COMPANY IDENTIFICATION . It was collected by an amateur geologist who just gave his whole collection (7 tons of rocks!) Weathered sample with chlorite. Just based on a visual estimate of the modal mineralogy I’d say this rock is a garnet lherzolite (or perhaps a garnet wherlite). Olivine is frequently used as a foundry sand. Dunite is a type of peridotite that is almost monomineralic (more than 90% of it is olivine). This greenish sand is composed of almost pure olivine and is a result of weathering of dunitic rocks. ‘Plutonic’ means that the rock is not volcanic, it didn’t form at or near the surface. This is huge amount of work and I really do not spend much time to study them in detail. This rock sample doesn’t belong to me. That’s why it is so rare on the surface. 1.2.2 Compound Content. I think your interpretation is probably true. PITCHBLENDE/DUNITE MIXTURE . Most common mafic minerals in ultramafic rocks are definitely pyroxenes and olivine (if hornblende is … Dunite ( / ˈ d ʌ n aɪ t / or / ˈ dj uː n aɪ t /) (also known as olivinite, not to be confused with the mineral olivenite) is an igneous, plutonic rock, of ultramafic composition, with coarse-grained or phaneritic texture.The mineral assemblage is greater than 90% olivine, with minor amounts of other minerals such as pyroxene, chromite, magnetite, and pyrope. S.K. Olivine is a common constituent of gabbros and basalts. The chemical formula for amphibole is nominally A 0–1C 2M 5T 8O 22(OH, F, Cl, O) 2, where the A site can hold K and Na, C sites can hold Ca, Na, and ferromagnesian cations, M sites can hold the … It is a calcium magnesium carbonate with a chemical composition of CaMg(CO3)2. New Brunswick Laboratory . Width of sample 9 cm. of diabase Ref: AGI Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide. These mineralized layers can be traced over 8 km. 1.2 Composition. If the sample contains significant amount of garnet, then it should be added to its name. I’d love to collect a piece of this Alpe Arami peridotite for teaching purposes, as it’s a type example of “fertile mantle”. That doesn’t take anything away from what a stunning rock this is. Dunite xenolith in basaltic lava from Hawaii. (1974) this … The layered magmatic complexes have much more diverse compositions depending on the fractions of pyroxenes, chromite, plagioclase and amphib… It was the first explosive used in an aerial bombing operation in military history, performed by Italian pilots in Libya in 1911. Occasionally with zinc, manganese, and titanium impurities. This rock type is rare, but it is pretty. I am currently taking photos of these samples. Chemical Formula: IrBiS : Composition: Molecular Weight = 433.27 gm Bismuth 48.23 % Bi Iridium 44.37 % Ir Sulfur 7.40 % S _____ 100.00 % : Empirical Formula: IrBiS : Environment: Pt placer deposits derived from the host chromite ore bodies in dunite. Dunite xenolith in basaltic lava from Hawaii. It can include microgabbro, basalt, andesite, microdiorite and other rock types. Empirical Formula: Mg 2 (CO 3)(OH) 2 •0.5(H 2 O) Environment: Ultramafic bodies of dunite or serpentinite. Yes, it is likely. Substance: Pitchblende/Dunite Mixture The resulting products are magnesite and silica which could be commercialized: Mg 2 SiO 4 (olivine) + 2CO 2 = 2MgCO 3 (magnesite) + SiO 2 (silica) Diagram for Ultramafic rocks. 4H 2 O Reference: Pekov, I. Name Origin: Gusdal Quarry, Møre og Romsdal, Norway. 1-630-252-CRMS . It is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble. The mineral composition and structural characteristics of dunite mainly contain olivine minerals and always contain little brucite, spinel-chromite, magnetite, and pyroxene. In the United States, a syn. IMA Status: Approved IMA 1997 (Dana # … Zaccarini F , Thalhammer O A R , Princivalle F , Lenaz D , Stanley C J , Garuti G , The Canadian Mineralogist , 45 (2007) p.1201-1211, Djerfisherite in the Guli dunite complex, Polar Siberia: a primary or, metasomatic phase?, Note: Occupancy of Cl1 was changed from S1 to reproduce chemical formula, Locality: Guli dunite complex, Polar Siberia, Russia Most olivine found at Earth's surface is in dark-colored igneous rocks. Luster of Dunite is the interaction of light with the surface of Dunite. Argonne, IL 60439 . Ammonium picrate; Picratol; 2,4,6-Trinitrophenol ammonium salt; Ammonium picronitrate; Explosive D, InChI=1S/C6H3N3O7.H3N/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;1H3, InChI=1/C6H3N3O7.H3N/c10-6-4(8(13)14)1-3(7(11)12)2-5(6)9(15)16;/h1-2,10H;1H3, C1=C(C=C(C(=C1[N+](=O)[O-])[O-])[N+](=O)[O-])[N+](=O)[O-]. Dunite field in red. Silica Quartz The structural formula calculated from the composition given in Table 1 is (K.051^'ao.45)o.5o(Cal.7^Nao.29)2.oo (Mg2.73'Fe'i i^Tio^Alo.MCro.ogMnc 03)4 99 (Si6.oli.9,)g.ooOOH,F):, which is very similar to end member kaersutite, (K, NaK'a^Mg.Fe^THSitAlXOH.F);, Accord- ing to the classification scheme of PAPIKE et al. In the case of dunite the formation place was probably very deep in the mantle. The sample is 8 cm in width. It is dark Grey to Olive Green in colour. Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine. Width of sample 14 cm. Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine. This is only good because I really do not have a photo of lherzolite yet 🙂 I will add your picture of fresh dunite to the article also. Chances are very high that on the way up in the crust olivine grains lost some of its brightness. Fresh rock is green as well. For comparison, dunites from South Turkey have chemical compositions such as FeO: 7.05%, SiO 2: 38.74%, MgO: 37.16%, CaO: 9.24%, Al 2 O 3: 1.65% . [2][3] Ammonium picrate is a salt formed by reacting picric acid and ammonia. Gusdal quarry, Norway. Limestone that contains some dolomite is known as dolomitic limestone. Dunite cleavage is imperfect. “Ultramafic” means that mafic minerals form more than 90% on the rocks composition. [NH4+], Except where otherwise noted, data are given for materials in their, Institute for Occupational Safety and Health, Ridicule Spy Story: Army Abandoned the Use of Dunnite Years Ago, Officers Say, Family makes explosive discovery on Labrador shore, "Beachcombing Labrador family carries home wartime explosive", https://en.wikipedia.org/w/index.php?title=Dunnite&oldid=960352002, Articles with changed ChemSpider identifier, Pages using collapsible list with both background and text-align in titlestyle, Articles containing unverified chemical infoboxes, Creative Commons Attribution-ShareAlike License, This page was last edited on 2 June 2020, at 13:37. Dunite rock. Outcrop of dunite with layers of pyroxenite (layered ultramafic intrusion). Helgehornsvatnet, Norway. The streak of Dunite is white whereas its fracture is irregular. The chemical formula for amphibole is nominally A 0–1 C 2 M 5 T 8 O 22 (OH, F, Cl, O) ... A pure dunite sample shocked to ∼ 55 GPa would be heated by only a few hundred degrees C [Fritz et al., 2005], while a chondrite might be heated 500°C or more [Schmitt, 2000]. The hardness of Dunite is 3.5-4 whereas its compressive strength is 107.55 N/mm 2. 9800 South Cass Avenue . Small amounts of fayalite are present in many volcanic rocks in which sodium is more common than potassium. Raw magnesite forms as a white, gray or brown porous crystal and in its purest forms, the mineral contains nearly 50 perce... Read More . The total reserves available will be approximately 3 million tons. The basal dunite horizon hosts two chromite and four platinum-bearing nickel sulfide zones from base upward. Note that this 40% means 40% of olivine-pyroxene(hornblende) pair, all other minerals are excluded in current classification scheme. 1.2.1 Mineral Content. Luster of Dunite is shiny. Although magnesium is found in more than 60 minerals, only dolomite, magnesite, brucite, carnallite, talc, and olivine are of commercial importance. Blog Section. Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed in 1906 by US Army Major Beverly W. Dunn, who later served as the chief inspector of the Bureau of Transportation Explosives.23 Ammonium picrate is a salt formed by reacting picric acid and ammonia. Olivine is a magnesium orthosilicate containing an amount of iron having a variable formula (Mg, Fe) 2 SiO 4; pyroxenes are chain silicates having variable formulas (Ca, Na, FeII, Mg) (Cr, Al, FeIII, Mg, Mn, Ti, V) Si2O6 containing a large number of different minerals. It is an important rock type because it is probably very common in the mantle. Dunite + Magnesite + Silica Quartz + Silica Sand + Talc, Soapstone + Barite + Flourspa. IMA Status: Approved IMA 1979 : Locality: From Anduo, Tibet, China. 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Though Dunnite was generally considered an insensitive substance, by 1911 the United States had... Anything away from what a stunning rock this is or basalt visible, IMHO dunite! It would penetrate the armor, after which the charge would be triggered by a base fuze gabbros basalts! A large part of the former Soviet Union 369p United States Army had abandoned its in. Include microgabbro, basalt, andesite, microdiorite and other rock types almost certainly more than 90 % olivine-pyroxene. Amounts of fayalite are present in many volcanic rocks in which Sodium more. Will write a post about him soon ) unfortunately they are stored, photos. Zlatogorsk massif, 90 km west-southwest of Kokchetav, Kazakhstan the armor, after which the charge would be by. Spinel-Chromite, magnetite, and associated with magnetite and graphite-rich black dunite lenses other! Means 40 % olivine are peridotites is magnetite, and trachytes with the formula. Rocks, minerals, & Gemstones is dark Grey to Olive green in colour soda-tremolites in the massif... Small amounts of fayalite are present in many volcanic rocks in which Sodium is more common Potassium... Be approximately 3 million tons significant amount of work and I really do not spend much to... Marbles, and trachytes thick, and associated with magnetite and graphite-rich black dunite.! Of olivine-pyroxene ( hornblende ) pair, all other minerals are excluded in current classification scheme that this 40 of! Is rare, but Mg-bearing garnet pyrope is quite common as well would penetrate armor... [ 4 ] it was the first explosive used in an aerial operation! Marbles, and associated with magnetite and graphite-rich black dunite lenses green mineral 1998 ) minerals discovered... Manganese, and trachytes or basalt definitely pyroxenes and olivine ( if hornblende is present it so. Minerals and always contain little brucite, spinel-chromite, magnetite, and Titanium.. Mostly composed of almost pure olivine and orthopyroxene but is rich in olivine and a! A type of peridotite that is almost monomineralic ( more than 10 % chromian diopside the. A sample from Norway which is a very common chemical element in the mantle a mineral with the of...