|
Ettringite
Ettringite is a hydrous calcium aluminium sulfate mineral with formula: . It is a colorless to yellow mineral crystallizing in the trigonal crystal system, system. The prismatic crystals are typically colorless, turning white on partial dehydration. It is part of the ettringite-group which includes other sulfates such as thaumasite and bentorite.Ettringite-group Mindat.org Discovery and occurrence 
Ettringite was first described in 1874 by ,Lehmann, J. (1874). Über den Ettringit, ein neues Mineral in Kalkeinschlüssen der Lava von Ettringen (Laacher Gebiet). N. Jb. Mineral. Geol. Paläont., 273–275. f ...
[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bentorite
Bentorite is a mineral with the chemical formula . It is colored violet to light violet. Its crystals are hexagonal to dihexagonal dipyramidal. It is transparent and has vitreous luster. It has perfect cleavage. It is not radioactive. Bentorite is rated 2 on the Mohs scale. The mineral was first described in 1980 by Shulamit Gross for an occurrence in the Hatrurim Formation of Danian age along the western margin of the Dead Sea, Israel. It was named by its discoverer, Shulamit Gross, for Yaakov Ben-Tor (1910–2002), Professor at the Hebrew University of Jerusalem and the University of California, San Diego, California, US, for his contributions to geology and mineralogy in Israel. Formation The only naturally occurring bentorite that has been discovered is in the Hatrurim Formation near the Dead Sea in Israel. The formation consists of a mixture of metamorphosed clays, limestones, and marls. The original sediments were enriched in chromium, and later experienced heating to > ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thaumasite
Thaumasite is a calcium silicate mineral, containing Si atoms in unusual octahedral configuration, with chemical formula Ca3 Si(O H)6( C O3)( SO4)·12 H2O, also sometimes more simply written as CaSiO3·CaCO3·CaSO4·15H2O. It occurs as colorless to white prismatic hexagonal crystals, typically as acicular radiating groups. It also occurs as fibrous masses. Its Mohs hardness is 3.5 and it has a specific gravity of 1.88 to 1.90. Optically it is uniaxial negative with indices of refraction of nω = 1.507 and nε = 1.468. It occurs as a hydrothermal alteration mineral in sulfide ore deposits and geothermal alteration of basalt and tuff. It occurs with zeolites, apophyllite, analcime, calcite, gypsum and pyrite. Thaumasite can also be formed in man-made concrete structures at the detriment of calcium silicate hydrates (C-S-H, with dashes denoting the non-stoichiometry of this hydrated cement phase acting as the "glue" in hardened cement paste) during cement alteration, especially ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portlandite
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2). Occurrence Portlandite occurs in a variety of environments. At the type location in Northern Ireland it occurs as an alteration of calc–silicate rocks by contact metamorphism of larnite– spurrite. It occurs as fumarole deposits in the Vesuvius area. In Jebel Awq, Oman, it occurs as precipitates from an alkaline spring emanating from ultramafic bedrock. In the Chelyabinsk coal basin of Russia it is produced by combustion of coal seams and similarly by spontaneous combustion of bitumen in the Hatrurim Formation of the Negev desert in Israel and the Maqarin area, Jordan. It also occurs in the manganese mining area of Kuruman, Cape Province, South Africa in the Kalahari Desert where it occurs as large crystals and masses. It occurs in association with afwillite, calcite, l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mayenite
Chlormayenite (after Mayen, Germany), Ca12Al14O32[☐4Cl2], is a rare calcium aluminium oxide mineral of cubic symmetry. It was originally reported from Eifel volcanic complex (Germany) in 1964. It is also found at Pyrometamorphism, pyrometamorphic sites such as in the Hatrurim Formation of Israel and in some burned coal dumps. It occurs in thermally altered limestone xenoliths within basalts in Mayen, Germany and Klöch, Styria, Austria. In the Hatrurim of Israel it occurs in thermally altered limestones. It occurs with calcite, ettringite, wollastonite, larnite, brownmillerite, gehlenite, diopside, pyrrhotite, grossular, spinel, afwillite, jennite, portlandite, jasmundite, melilite, kalsilite and corundum in the limestone xenoliths. In the Hatrurim it occurs with spurrite, larnite, grossite and brownmillerite. Synthetic Dodecacalcium hepta-aluminate, Ca12Al14O33 and Ca12Al14O32(OH)2 are known, they are stabilized by moisture instead of chlorine. The formula can be written as [ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afwillite
Afwillite is a calcium hydroxide nesosilicate mineral with formula Ca3(SiO3OH)2·2H2O. It occurs as glassy, colorless to white prismatic monoclinic crystals. Its Mohs scale hardness is between 3 and 4. It occurs as an alteration mineral in contact metamorphism of limestone. It occurs in association with apophyllite, natrolite, thaumasite, merwinite, spurrite, gehlenite, ettringite, portlandite, hillebrandite, foshagite, brucite and calcite. It was first described in 1925 for an occurrence in the Dutoitspan Mine, Kimberley, South Africa and was named for Alpheus Fuller Williams (1874–1953), a past official of the De Beers diamond company. Afwillite is typically found in veins of spurrite and it belongs to the nesosilicate sub-class. It is monoclinic, its space group is P2 and its point group is 2. Formation It is suggested that afwillite forms in fractured veins of the mineral spurrite. Jennite, afwillite, oyelite and calcite are all minerals that form in layers within spur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weathering
Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are either physical or chemical. The former involves the breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after the rock breaks down combine with organic material to create so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larnite
Larnite is a calcium silicate mineral with the formula . It is the calcium member of the olivine group of minerals. It was first described from an occurrence at Scawt Hill, Larne, Northern Ireland in 1929 by Cecil Edgar Tilley and named for the location. At the type locality it occurs with wollastonite, spurrite, perovskite, merwinite, melilite and gehlenite. It occurs in contact metamorphosed limestones and chalks adjacent to basaltic intrusives. Dicalcium silicate is chemically β–, sometimes represented by the idealized oxide formula also noted in the cement chemist notation (CCN). When used in the cement industry, the mineral is usually referred to as belite Belite is an industrial mineral important in Portland cement manufacture. Its main constituent is dicalcium silicate, Ca2SiO4, sometimes formulated as 2 CaO · SiO2, SiO2 (C2S in cement chemist notation). Etymology The name was given by Alfred E .... References * Nesosilicates Monoclinic minerals Mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hatrurim Formation
The Hatrurim Formation or Mottled Zone is a geologic formation with outcrops all around the Dead Sea Basin: in the Negev Desert in Israel, in the Judaean Desert on the West Bank, and in western Jordan. It includes late Cretaceous to Eocene aged impure limestone along with coal bearing chalk and marl. The rocks have been subjected to pyrometamorphism resulting from combustion of contained or underlying coal or hydrocarbon deposits. The formation is named for exposures in the Hatrurim Basin which lies west of the Dead Sea. During the 1960s, a group of scientists from the Hebrew University of Jerusalem, including Yaakov Ben-Tor, and Lisa Heller-Kallai, discovered that the Hatrurim Formation contained several rare, if not unique, mineral assemblages. The formation is the type locality for five unusual minerals and noted for other minerals serving as reference for mineral phases formed at high temperature in the clinker of Portland cement. Shulamit Gross, an Israeli geologist and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Israel
Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Israeli-occupied territories, It occupies the Occupied Palestinian territories, Palestinian territories of the West Bank in the east and the Gaza Strip in the south-west. Israel also has a small coastline on the Red Sea at its southernmost point, and part of the Dead Sea lies along its eastern border. Status of Jerusalem, Its proclaimed capital is Jerusalem, while Tel Aviv is the country's Gush Dan, largest urban area and Economy of Israel, economic center. Israel is located in a region known as the Land of Israel, synonymous with the Palestine (region), Palestine region, the Holy Land, and Canaan. In antiquity, it was home to the Canaanite civilisation followed by the History of ancient Israel and Judah, kingdoms of Israel and Judah. Situate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northern Cape Province
The Northern Cape ( ; ; ) is the largest and most sparsely populated province of South Africa. It was created in 1994 when the Cape Province was split up. Its capital is Kimberley. It includes the Kalahari Gemsbok National Park, part of the Kgalagadi Transfrontier Park and an international park shared with Botswana. It also includes the Augrabies Falls and the diamond mining regions in Kimberley and Alexander Bay. The Namaqualand region in the west is famous for its Namaqualand daisies. The southern towns of De Aar and Colesberg found within the Great Karoo are major transport nodes between Johannesburg, Cape Town and Gqeberha. Kuruman can be found in the north-east and is known as a mission station. It is also well known for its artesian spring and Eye of Kuruman. The Orange River flows through the province, forming the borders with the Free State in the southeast and with Namibia to the northwest. The river is also used to irrigate the many vineyards in the arid reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous
Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Geological significance Igneous and metamorphic rocks make up 90–95% of the top of the Earth's crust by volume. Igneous rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
