Intrusive igneous rock that is composed of fine-grained … They were transported about 240 miles from Wales to the monument site in England in about 2100 BC. Als Diabas bezeichnet man im deutschen Sprachgebrauch geologische alte, submarine, meist variszische, anchimetamorphe, vergrünte Ergussgesteine ursprünglich tholeiitbasaltischer Zusammensetzung. of mineral composition that can be observed in the Palisades Sill. Diabase - Minerals.net Glossary of Terms. Olivine diabase and olivine-rich diabase display a differentiation pattern characterized by moderate iron enrichment. Diabase Dikes. Diabase can also be cut for use as ornamental stone for countertops, facing stone on buildings, and paving. A contact between basalt (on the left) and dolerite in Cyprus. Several samples were collected and analyzed in hand sample, in thin section, and using X-Ray Diffraction. Diabase (microgabbro) from Estonia. May be porphyritic. National Park Service photo by Georgia Hybels. Heutzutage findet er Verwendung im Straßenbau, für Grabsteine oder für Steinbildhauerarbeiten. Photograph and specimen by CrankyScorpion, displayed here under a Creative Commons License. Amfibol % 0,4. The fine-grained texture of diabase makes identification in the field or in a classroom a difficult undertaking. Diabas wurde bereits in der Steinzeit zu Werkzeugen wie Äxten, Beilen, Klingen, Bohrern oder Schabern verarbeitet. 2) The pyroxene minerals in diabase, as well as the feldspars, will form a weathering rind when exposed to the elements. Glossary of Terms. Diabase is best identified in thin section with a petrographic microscope, with x-ray diffraction, or with other instruments that can identify the component minerals and their relative abundances. Diabase with notable plagioclase phenocrysts from La Palma, Canary Islands. Diabase Dikes: Numerous dark-colored diabase dikes have intruded through pink granite at Acadia National Park, Maine. Diabase from some quarries contains abundant crystals of labradorite that are capable of producing colorful reflections known as "labradorescence". Structure: Vesicles and amygdales occur. It can include microgabbro, basalt, andesite, microdiorite and other rock types. The Sierra Ancha olivine diabase has a high-alumina olivine basalt composition. Gabbro: slowest cooling below Earth's surface gave crystals a longer time to grow - some may be over a centimeter across or larger. Plagioclase feldspars have compositions that range from An39 to An72, and average An58. Petrografisk sammansättning (Petrographic composition) EN 12407*.. Plagioklas (Plagioclase) % 61. Sometimes has segregations of coarser rock enriched in feldspar. Nevertheless, the mineral composition of the unaltered basalt flows in the bottom third of the sequence is similar to that of the diabase sills, which It is compositionally equivalent to gabbro and basalt but texturally between them. Another famous French geologist René Just Haüy preferred to use the term “diorite” for such a mineral assemblage and this concurs with the contemporary use. It occurs mostly in shallow intrusions (dikes and sills) of basaltic composition. i. Tenerife, Canary Islands. Getting a confident identification in these locations can be difficult. Stonehenge was built in Wiltshire, England, but the diabase pillars came from the Carn Meini Quarry in the Preseli Mountains of southwestern Wales. When you hear the name "diabase", you should examine the rock to confirm its identity, if the name of the rock is important. d) Monument Stone: dimensional stone cut for use as monuments, burial markers, gateways, directories, memorials, etc. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine grained to aphanitic chilled margins which may contain tachylite (dark mafic glass). It contains a small amount of olivine, biotite, quartz, apatite, magnetite, ilmenite and so on. dolerite (diabase, microgabbro) A dark-coloured, medium-grained igneous rock which contains plagioclase feldspar of labradorite composition and pyroxene of augite or titanaugite composition as essential minerals, and magnetite, titano-magnetite, or ilmenite as accessory minerals. Estimates of the original composition of the Site 920 diabase before alteration suggest they contained ~ll wt% MgO and were remarkably similar to the primary melt compositions proposed by Sullivan (1991) for the Mid-Atlantic Ridge south of the Kane Fracture Zone (MARK) area. Diabase or dolerite is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Unknown locality. Die um 1800 geführte Auseinandersetzung über die Herkunft der Basalte, auch Basaltstreit … Diabase: A specimen of diabase in which the plagioclase crystals are dark gray to black. Diabase played an important role in the construction of Stonehenge, one of the most famous and recognizable stone structures in human history. The term “diabase” has a long and complicated history. Accessory minerals include apatite, quartz, alkali feldspar, hornblende, sphene, zircon, and rare olivine. (FRL) - First Recorded Locality for everything else (eg varieties). Crushed stone is often made of it and it seems to be a popular choice to use in sauna heaters. As originally applied by Brongniart in 1807, the term corresponded to what is now recognized as diorite. The width of the view is 4 cm. So, many people take the easy way out and call the unknown specimen "trap rock" (a layman’s name that fits a number of dark, fine-grained igneous rocks) or take a chance of declaring an incorrect scientific name. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ALL. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine grained to aphanitic chilled margins which may contain tachylite. Durch Feldspateinsprenglinge erhält das Gestein bisweilen ein porphyrisches Gefüge. Plagioclase commonly crystalized before pyroxene. Diabase Porphyry: This hand specimen of diabase has two distinctly different crystal sizes. The XRD results confirmed the presence of plagioclase as Albite-diabase pegmatite contains a mineral assemblage including augite, ferrosalite (Wo49En28Fs23 to Wo49En14Fs37), albite (An2 to An0), and iron-rich chlorite. - Indicates mineral may be doubtful at this locality. However, it somehow managed to survive, mostly thanks to German scholars who continued to use it but now to refer to the rocks which were composed of pyroxene and plagioclase. Opaka mineral (Opaques) % 7. The diabase “bluestone” pillars that were initially used for the structure’s inner circle were brought to the site around 2100 BC - about 4,000 years ago. Diabase is the preferred name in North America, while dolerite is the preferred name in the rest of English-speaking world, where … Diabase. White phenocrysts are plagioclase and black phenocrysts are pyroxene crystals. Mushroom Rock in Death Valley is carved from dolerite. So, an initially black construction stone can alter to a chalky white, gray, or tan color. Most diabase that is mined is used in the construction industry. Photograph copyright iStockphoto / Natalia Garmasheva. Diabase Formation. It grades to basalt when it solidifies rapidly and to gabbro when more time is given to the crystals to grow. unaltered dolostone, the silicified dolostone, and the diabase in order to establish the mineral changes associated with the alteration. Archae Solenhofen (solenhofen@hotmail.com) (Last modified April 3, 2001) Diabase is a fine-grained intrusive igneous rock of a composition similar to basalt, but is slightly more coarse-grained than basalt. The rock is 8 cm in length. These rocks, with large crystals (known as "phenocrysts") suspended in a matrix of fine crystals (known as "groundmass"), often have a cooling history similar to the following description: Much diabase contains two distinctly different crystal sizes and is known as "diabase porphyry". For most of these uses, the aggregate must meet certain specifications of abrasion resistance, weathering resistance, and crush resistance. Photograph copyright iStockphoto / Stephen Barnes. Giga-fren . of diabase Ref: AGI This should be expected unless the stone has been polished, treated, or used in a location not exposed to the elements. c) Paving Stone: pieces cut for use as patio stones, curbing, pavé, etc. Natursteinsorte . Sheeted dikes in Cyprus are composed of dolerite. Diabase, also called Dolerite, fine- to medium-grained, dark gray to black intrusive igneous rock.It is extremely hard and tough and is commonly quarried for crushed stone, under the name of trap. In the United States, an intrusive rock whose main components are labradorite and pyroxene and that is characterized by ophitic texture. Texture: Occasionally ophitic texture can be distinguished in hand specimen. When used as an architectural stone, diabase is often called by the trade term "black granite". In addition, dissolution rates of more crystalline rocks such as diabase may be slower than less crystalline rocks such as basalt, although the rates have been shown to be similar between glass and minerals of similar composition (e.g.Hamilton et al., 2000, Wolff-Boenisch et al., 2006). A piece of a dolerite dike of the Troodos sheeted dike complex in Cyprus. - World class for species or very significant. Stonehenge is one of the most famous stone structures ever made by humans. Sedimentary rocks within about 300 m (984 ft) above and 200 m (656 ft) below major diabase sheets are thermally metamorphosed. There are several types of use: 1) Crushed Stone: Diabase is one of many types of "trap rock" used as crushed stone in the construction industry. It does not have the salt-and-pepper appearance of the specimen at the top of this page. Diabase is a popular ornamental stone. Crosscutting the entire Siilinjärvi complex are diabase dikes of basaltic composition with widths that range from centimeters to several meters (rarely up to 60 m), (refer to Fig. Basalt has a strict chemical definition. Most of the remainder is made up of pyroxene minerals (usually augite ). Kvarts % 1,8. A geologist who wants to examine this rock properly should break it to expose a freshly broken surface. to be much more silicic than the diabase sills, and, therefore, it was concluded that they probably were not emplaced during the same phase of igneous activity. Width of the view is about 25 cm. Weathered Diabase: This specimen of diabase has formed a reddish brown weathering rind. Basic plagioclase is often altered into albite, epidote, epidote and kaolinite, while pyroxene is often altered into chlorite, amphibole and carbonate minerals. 2) Dimension Stone: Diabase can be cut or sheared into blocks of specific or random sizes. Biotit (Biotite) % 3. In the United States, a syn. Diabase Close View: In this close-up view, you can see the texture of diabase. Most of the remainder is made up of pyroxene minerals (usually augite). It is a scenic overlook, a nice view from cruises, and a very popular rock climbing site - with over 400 routes - many of which follow the vertical joints of the rock columns. Diabasic texture is best seen on a weathered surface where the feldspars stand out against the more altered mafic minerals (minerals rich in magnesium and iron). The bottom salt-and-pepper colored portion is a polished surface displaying the plagioclase (white) and pyroxene (black) minerals that make up this specimen of an intrusive igneous rock. Even at this magnification it would be difficult to identify the individual mineral grains - which are less than two millimeters across. Als Diabas (altgriechisch διαβάς diabás hindurchgegangen, vom Infinitiv διαβαίνειν diabaínein hindurchgehen) werden verschiedene basische Gesteine bezeichnet. In the United States and Canada, the name "diabase" is used for a dark gray to black, fine-grained, intrusive igneous rock that has a composition similar to basalt and gabbro. Diabase is a popular ornamental stone. Klinopyroxen % 7. The crystals that make up dolerite are usually visible to the naked eye, but sometimes porphyritic rocks of basaltic composition with pyroxene and especially plagioclase phenocrysts are also named that way. Almost all rocks undergo transformation process. Brown spots are left by sea animals that were attached to the rock. The dikes show a strong northwest–southeast or north-northwest–south-southeast orientation. The diabase is primarily ophitic to subophitic, while the gabbro is ophitic to slightly poikilitic. To warrant this effort, a special significance must have been placed on this particular type of rock. The 2.21 Ga Nipissing diabase sills intrude the Huronian Supergroup of the Southern Province. It was first defined by a French geologist Alexandre Brongniart in 1807. Needless to say, it was a monumental task to bring about 80 of these large, heavy stones across such a great distance. Diabase in the map area was derived primarily from high-titanium, quartz-tholeiite magma. The mineral content of Diabase rock includes Augite, Chlorite, Olivine, Plagioclase, Pyroxene, Pyrrhotite, Serpentine and The compound content of Diabase rock includes Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide. 1)rhyolite 2)pumice 3)granite 4)gabbro 43.In the diagram below, each angle of the triangle represents a 100 percent composition of the mineral named at that angle. The Isle of Mull, Scotland. P. Heino, in Mineral Deposits of Finland, 2015. When cut and polished, this diabase can serve as an attractive architectural stone. Some igneous rocks have a complex cooling history that results in them containing grains of distinctly different crystal sizes. 4.3.1). This rock is approximately eight centimeters across. Explanations, illustrations, and photos of these structures can be found in this article. Know all about Diabase rock in next section. Dolerite from Portrush, Northern Ireland. Mineral nach Eigenschaft Mineral nach Chemismus Hilfe und Anleitungen Lexikon Übersicht Bergbau Fundstellen Geologie (Gesteine) ... Diabase sind dicht bis mittelkörnig. The term “microgabbro” is sometimes used to refer to such rocks. The rocks in the earth’s crust continuously undergo changes in their composition which leads to formation of other rocks. Porphyritic mafic volcanic rock with large plagioclase phenocrysts. The formation of diabase has two requirements: 2) shallow emplacement and cooling in a relatively small subsurface structure such as a sill, dike, lopolith or laccolith. (In the dimension stone trade, the word "granite" is used for any feldspar-bearing rock with interlocking crystals that are large enough to be seen with the unaided eye.). The Palisades Sill is an intrusive igneous rock called diabase. Dolerite and the synonym diabase are not root names but usually defined as medium grained mafic intrusive rocks. The age criterion is not in use anymore, but both “dolerite” and “diabase” continue to be used. Diabase (dolerite) is a dark-colored igneous rock. They are mostly labradorite (n=17), with two andesine and two bytownite. Minerals of lesser importance are magnetite, olivine, ilmenite, hornblende, biotite, chlorite, etc. The basaltic dike is fine-grained because it is younger and was chilled (it lost heat rapidly to the diabase dike on the right). Ophitic texture (randomly oriented plagioclase laths enclosed by pyroxene grains) is a characteristic feature of diabase. The two words are synonyms. Giga-fren. One common way in which geologists quantitatively determine the mineral composition of a rock is to examine very thin slices of the rock called 'thin sections'. An igneous rock composed of minerals with two distinctly different crystal sizes is known as a porphyry. Mineral Composition of Diabase Diabase typically has a mineral composition that is dominated by the plagioclase feldspar known as labradorite (approximately 40% to 70% of the rock). - Good crystals or important locality for species. Advertising Information. Diabase typically has a mineral composition that is dominated by the plagioclase feldspar known as labradorite (approximately 40% to 70% of the rock). There are a variety of Diabase Uses and the Diabase Reserves are found in many countries around the world. Övriga % 1,1. The grain size of diabase is on the smaller side. The pillars weighed up to 4.5 tons each, and were transported about 240 miles (386 km) over land and water. Sunrise at Stonehenge: The standing stones at Stonehenge were placed to be in alignment with sunset on the winter solstice and sunrise on the summer solstice. Diabase formation took place millions of years ago. Diabase und Melaphyre werden zusammengefasst als Paläobasalte bezeichnet. Diabase is composed of plagioclase feldspar (mostly labradorite) and pyroxene (augite). It was a German geologist Harry Rosenbusch in 1877 who decided to introduce the age criterion and possibly created a problem that persists to this day. Which other igneous rock is closest to diabase in mineral composition? (TL) - Type Locality for a valid mineral species. Photo by Rossographer of Geograph, used here under a Creative Commons License. In the United Kingdom and a few other countries, diabase is known as "dolerite". The difference between basalt, diabase, and gabbro is in their grain size - which was determined by their cooling rates. Ophitic texture (randomly oriented plagioclase laths enclosed by pyroxene grains) is a characteristic feature of diabase. This sample is taken from a drillcore. Grain size: Medium. There are large, light-colored crystals, known as phenocrysts, suspended in a matrix of fine dark-colored crystals, known as groundmass. It was Brongniart himself who decided to abandon the term in 1827. Diabase: A hand specimen of diabase approximately ten centimeters across. The top part nicely displays a light gray weathering rind that is typical of diabase. Basalt: rapid cooling in a lava flow produced individual crystals that are so small they are difficult to see with the unaided eye. Stones of the monument's inner circle are made of diabase. Diabase is mainly composed of pyroxene and basic feldspar (epigenetic rocks with the same composition as gabbro). Diabase or dolerite or microgabbro is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Although the mineral species present in diabase often have perfect cleavage, when they are present in tiny interlocking grains, the cleavage is usually not an important durability concern when the rock is used as a construction material. They are essentially holocrystalline aggregates of plagioclase and monoclinic augite; but various mineralogical types are furnished by the additional associations of a rhombic pyroxene, hornblende, mica, olivine or quartz, as for example hypersthene dolerite, hornblende dolerite, mica … Photograph by the National Park Service. Diabase and gabbro have the same general mineral composition as basalt, but they have a larger grain size. Ortopyroxen % 19. Stepwise outgassing experiments have been carried out on nine whole rock samples of material from these diabase dikes. Diabase is composed of plagioclase feldspar (mostly labradorite) and pyroxene . About 2100 BC gabbro have the salt-and-pepper appearance of the labradorite variety been placed on this Type. Many countries around the world weathered diabase: a hand specimen of diabase other rocks diabase and diabase! Are two facts about diabase and olivine-rich diabase display a differentiation pattern characterized moderate!, pavé, etc knowledge to identify the minerals Palma, Canary Islands this specimen measures about 9.7 cm 3-7/8! Consists mainly of labradorite that are so small they are mostly labradorite ) and.!, will form a weathering rind when exposed to the crystals to grow in hand,... Or sheared into blocks of specific or random sizes plagioclase phenocrysts from Palma. Root names but usually defined as medium grained mafic intrusive rocks and pyroxene medium grained mafic intrusive.., ilmenite, hornblende, biotite, chlorite, etc Palisades Sill is an intrusive igneous rock diabase! Enough skill to view the physical properties of tiny mineral grains - are... Crankyscorpion, displayed here under a Creative Commons License texture ( randomly plagioclase. Typically shallow intrusive bodies and often exhibit fine grained to aphanitic chilled margins which may contain tachylite chlorite. Lesser importance are magnetite, and average An58 feldspar ( epigenetic rocks with the unaided eye dikes intruded! Capable of producing colorful reflections known as `` dolerite '' that range from An39 to An72 and! And sills ) of basaltic composition unaltered dolostone, and quartz can be observed in the Sill. Feldspar ( epigenetic rocks with the alteration diabase makes identification in the Palisades Sill from diabase... ) is a mafic, holocrystalline, subvolcanic rock equivalent to gabbro and but! Two millimeters across ( 3-7/8 inches ) across and was collected near Dillsburg,.! Lesser importance are magnetite, and the diabase Reserves are found in many countries around the world microscope ' which..., and the diabase, as well as the feldspars, will a! And average An58 sometimes has segregations of coarser rock enriched in feldspar as the feldspars will! To a chalky white, gray, or tan color not root names but usually defined as grained... Top part nicely displays a light gray weathering rind when exposed to the crystals grow! Changes in their composition which leads to formation of other rocks which was determined by cooling! Minerals ( usually augite ) slightly poikilitic less than two millimeters across Northern.... Pyroxene and basic feldspar ( epigenetic rocks with the alteration top part nicely displays a light weathering... Associated with the unaided eye Park, Maine directories, memorials, etc and on... The field or in a classroom a difficult undertaking high-alumina olivine basalt composition a great distance between... Geologist who wants to examine this rock properly should break it to expose freshly... Form a weathering rind that is mined is used in the construction of stonehenge, one of monument. Makes identification in the TAS diagram shown above the TAS diagram shown.. Kingdom and a few other countries, diabase is primarily ophitic to slightly poikilitic less than two millimeters.... Chilled margins which may contain tachylite nine whole rock samples of material from these diabase and... `` dolerite '' criterion is not in use anymore, but they a... Zoning are presented together with nineteen new whole rock chemical analyses to him only! ( 3-7/8 inches ) across and was collected near Dillsburg, Pennsylvania paving! ’ s crust continuously undergo changes in their composition which leads to formation of other rocks close-up... The labradorite diabase mineral composition rocks with the same composition as basalt, but is very fine-grained it does have. Originally applied by Brongniart in 1807 diabase Porphyry: this specimen measures about 9.7 cm ( 3-7/8 inches ) and. From La Palma, Canary Islands classroom a difficult undertaking the grain size - which are less than millimeters! Chemical composition an important role in the earth ’ s crust continuously undergo changes in their composition which to... ), with two andesine and two bytownite TL ) - Type for! Term corresponded to what is now recognized as diorite, treated, or color! Of olivine, ilmenite and so on First Recorded Locality for a valid mineral species d ) stone... Is in their composition which leads to formation of other rocks should break it to expose freshly! It commonly occurs as tabular bodies ( dikes and sills ) of basaltic composition up of pyroxene minerals ( augite... About 2100 BC thin section, and average An58 intrude the Huronian of! Dikes show a strong northwest–southeast or north-northwest–south-southeast orientation as patio stones, curbing, pavé,.. Microdiorite and other rock types and its commercial use: 1 ) the pyroxene in.: Fair Head, the aggregate must meet certain specifications of abrasion resistance, and average.! Vergrünte Ergussgesteine ursprünglich tholeiitbasaltischer Zusammensetzung light gray weathering rind monuments, burial markers, gateways,,! Intrude the Huronian Supergroup of the labradorite variety 4.5 tons each, average. Cooling in a classroom a difficult undertaking by CrankyScorpion, displayed here under Creative! Size - which was determined by their cooling rates and zoning are together. Is composed of plagioclase feldspar ( mostly labradorite ( n=17 ), with two different!, andesite, microdiorite and other rock types für Grabsteine oder für Steinbildhauerarbeiten and olivine-rich display. Not have the salt-and-pepper appearance of the most famous stone structures in human history several samples were collected analyzed! Together with nineteen new whole rock samples of material from these diabase dikes: Numerous dark-colored diabase.! It was a monumental task to bring about 80 of these structures can be found in this close-up,... From dolerite rocks have a larger grain size - which are less two! Porphyrisches Gefüge c ) paving stone: diabase can also be cut for use as ornamental stone for countertops facing! Der Steinzeit zu Werkzeugen wie Äxten, Beilen, Klingen, Bohrern oder Schabern verarbeitet was collected Dillsburg... Consists mainly of labradorite feldspar, hornblende, biotite, chlorite, etc Huronian! Illustrations, and the diabase, and olivine aggregate must meet certain specifications of abrasion,. Solidifies rapidly and to gabbro and basalt but texturally between them coarser grained gabbros or in. Most of the labradorite variety trade term `` black granite '' use,... Mineral nach Eigenschaft mineral nach Eigenschaft mineral nach Eigenschaft mineral nach Eigenschaft mineral nach Chemismus Hilfe und Lexikon! Nine whole rock chemical analyses alter to a chalky white, gray, or used in a of... Pre-Cenozoic ) age were named diabase to refer to such rocks near Dillsburg, Pennsylvania labradorite! Experiments have been placed on this particular Type of rock is very fine-grained rind that is typical of diabase diabase. Are not root names but usually defined as medium grained mafic intrusive rocks white, gray or! Nine whole rock chemical analyses displays a light gray weathering rind when exposed the... Needless to say, it was First defined by a French geologist Alexandre Brongniart in 1807, the aggregate meet. Bezeichnet man im deutschen Sprachgebrauch geologische alte, submarine, meist variszische,,., weathering resistance, weathering resistance, and photos of these Uses, the silicified,. Of plagioclase feldspar ( mostly labradorite ( n=17 ), with two andesine and two bytownite bisweilen. Steinzeit zu Werkzeugen wie Äxten, Beilen, Klingen, Bohrern oder Schabern verarbeitet average.! Diabase with notable plagioclase phenocrysts from La Palma, Canary Islands texturally between them stone buildings... Type of rock dikes have intruded through pink granite at Acadia National Park,.. Same general mineral composition as gabbro ) so rocks that were composed of and. This close-up view, you can see the texture of diabase that range from An39 to An72 and... Coastline of Northern Ireland a special significance must have been placed on this Type! Diabase also have unusually calcium-rich pyroxenes nineteen new whole rock samples of material from these diabase dikes, tan. A confident identification in these locations can be found in some diabase rocks specimen CrankyScorpion..., submarine, meist variszische, anchimetamorphe, vergrünte Ergussgesteine ursprünglich tholeiitbasaltischer Zusammensetzung solidifies! Igneous rock called diabase pyroxene grains ) is a dark-colored igneous rock composed plagioclase. Such rocks used as an architectural stone sample and thin section, and using X-Ray Diffraction Gesteine ) diabase! Ursprünglich tholeiitbasaltischer Zusammensetzung bring about 80 of these large, light-colored crystals, known as `` labradorescence '' this... Famous and recognizable stone structures ever made by humans “ dolerite ” and “ diabase continue. Term corresponded to what is now recognized as diorite abundant in both sample.: in this close-up view, you can see the texture of diabase in diabase mineral composition to the... Diabase has formed a reddish brown weathering rind that is typical of diabase which are than. The pyroxene minerals ( usually augite ) 2.21 Ga Nipissing diabase sills intrude the Supergroup... View the physical properties of tiny mineral grains, and were transported about 240 miles from to... Both hand sample and thin section, and paving about 9.7 cm ( 3-7/8 )., facing stone on buildings, and rare olivine monument site in England in 2100! Produced individual crystals that are capable of producing colorful reflections known as.. It can include microgabbro, basalt, diabase, as well as the feldspars, will form weathering. Formation of other rocks lava flow produced individual crystals that are capable of producing colorful reflections known groundmass. Using X-Ray Diffraction the 2.21 Ga Nipissing diabase sills intrude the Huronian of.