|
Mineral Group
In geology and mineralogy, a mineral group is a set of mineral species with essentially the same crystal structure and composed of chemically similar elements.Stuart J. Mills, Frédéric Hatert, Ernest H. Nickel, and Giovanni Ferraris (2009): "The standardisation of mineral group hierarchies: application to recent nomenclature proposals". ''European Journal of Mineralogy'', volume 21, number 5, pages 1073-1080. For example, the amphibole group consists of 15 or more mineral species, most of them with the general unit formula , where A is a trivalent cation such as or , B is a divalent cation such as , , or , and C is an alkali metal cation such as , , or . In all these minerals, the anions consist mainly of groups of four tetrahedra connected by shared oxygen corners so as to form a double chain of fused six-member rings. In some of the species, aluminum may replace some silicon atoms in the backbone, with extra B or C cations to balance the charges. List of groups * Alun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancrinite
Cancrinite is a complex carbonate and silicate of sodium, calcium and aluminium with the formula Na6Ca2 water">H2O. It is classed as a member of the feldspathoid group of minerals; the alkali feldspars that are poor in silica. Yellow, orange, pink, white or even blue, it has a vitreous or pearly lustre (mineralogy), luster; a Mohs scale of mineral hardness, hardness of 5–6 and an uneven conchoidal fracture. It is unusual among the silicate minerals in that it will effervesce with hydrochloric acid due to the associated carbonate ions. Found originally in 1839 in the Ural Mountains, it is named after Georg von Cancrin, a Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...n minister of finance. References Calcium minerals Sodium minerals Aluminium minerals Carbonate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyroxene
The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron (Fe(II)) or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron (Fe(II) or Fe(III)). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes. The name ''pyroxene'' is derived from the Ancient Greek w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mica Group
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is common in igneous and metamorphic rock and is occasionally found as small flakes in sedimentary rock. It is particularly prominent in many granites, pegmatites, and schists, and "books" (large individual crystals) of mica several feet across have been found in some pegmatites. Micas are used in products such as drywalls, paints, and fillers, especially in parts for automobiles, roofing, and in electronics. The mineral is used in cosmetics and food to add "shimmer" or "frost". Properties and structure The mica group comprises 37 phyllosilicate minerals. All crystallize in the monoclinic system, with a tendency towards pseudohexagonal crystals, and are similar in structure but vary in chemical composition. Micas are translucent to opaque ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langbeinites
Langbeinites are a family of crystalline substances based on the structure of langbeinite with general formula , where M is a large univalent cation (such as potassium, rubidium, caesium, or ammonium), and M' is a small divalent cation (for example, magnesium, calcium, manganese, iron, cobalt, nickel, copper, zinc or cadmium). The sulfate group, , can be substituted by other tetrahedral anions with a double negative charge such as tetrafluoroberyllate (), selenate (), chromate (), molybdate (), or tungstates. Although monofluorophosphates are predicted, they have not been described. By redistributing charges other anions with the same shape such as phosphate also form langbeinite structures. In these the M' atom must have a greater charge to balance the extra three negative charges. At higher temperatures the crystal structure is cubic P213. However, the crystal structure may change to lower symmetries at lower temperatures, for example, P21, P1, or P212121. Usually this temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ilmenite
Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printing inks, fabrics, plastics, paper, sunscreen, food and cosmetics. Structure and properties Ilmenite is a heavy (specific gravity 4.7), moderately hard (Mohs hardness 5.6 to 6), opaque black mineral with a submetallic luster. It is almost always massive, with thick tabular crystals being quite rare. It shows no discernible cleavage, breaking instead with a conchoidal to uneven fracture. Ilmenite crystallizes in the trigonal system with space group ''R''. The ilmenite crystal structure consists of an ordered derivative of the corundum structure; in corundum all cations are identical but in ilmenite Fe2+ and Ti4+ ions occupy alternating layers perpendicular to the trigonal c axis. Pure ilmenite is paramagnetic (showing only very weak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humite (mineral Group)
The humite groupGaines et al (1997) Dana's New Mineralogy Eighth Edition, Wiley is a group of nesosilicates with the general formula . When A is predominantly magnesium we have the humite subgroup: *norbergite, * chondrodite, *humite, *clinohumite, The manganese-humite subgroup has members *alleghanyite, * manganhumite, * sonolite, and the leucophoenicite subgroup has members * ribbeite, * leucophoenicite, * jerrygibbsite Chondrodite is the most common member of the humite group. It may contain Ti up to 9.6% . Chondrodite from Sterling Hill Mine and Franklin Mine contains zinc to 11.5% ZnO and Mn to 36% MnO, and grades to alleghanyite. The humite minerals commonly alter to serpentine or Mg-rich chlorite and dissolve by weathering, leaving iron oxide An iron oxide is a chemical compound composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Ferric oxyhydroxides are a related class of compounds, perhaps the b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematite
Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . It has the same crystal structure as corundum () and ilmenite (). With this it forms a complete solid solution at temperatures above . Hematite occurs naturally in black to steel or silver-gray, brown to reddish-brown, or red colors. It is mined as an important ore mineral of iron. It is electrically conductive. Hematite varieties include ''kidney ore'', ''martite'' ( pseudomorphs after magnetite), ''iron rose'' and ''specularite'' ( specular hematite). While these forms vary, they all have a rust-red streak. Hematite is not only harder than pure iron, but also much more brittle. The term ''kidney ore'' may be broadly used to describe botryoidal, mammillary, or reniform hematite. Maghemite is a polymorph of hematite (γ-) with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garnet
Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, defining distinct species. These species fall into two primary solid solution series: the pyralspite series (pyrope, almandine, spessartine), with the general formula [Mg,Fe,Mn]3Al2(SiO4)3; and the ugrandite series (uvarovite, grossular, andradite), with the general formula Ca3[Cr,Al,Fe]2(SiO4)3. Notable varieties of grossular include Grossular#Hessonite, hessonite and tsavorite. Etymology The word ''garnet'' comes from the 14th-century Middle English word ''gernet'', meaning 'dark red'. It is borrowed from Old French ''grenate'' from Latin language, Latin ''granatus,'' from ''granum'' ('grain, seed'). This is possibly a reference to ''mela granatum'' or even ''pomum granatum'' ('pomegranate', ''Punica granatum''), a plant whose fruits conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feldspathoid
The feldspathoids are a group of tectosilicate minerals which resemble feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocl ...s but have a different structure and much lower silica content. They occur in rare and unusual types of igneous rocks, and are usually not found in rocks containing primary quartz. A notable exception where feldspathoids and quartz-bearing rocks are found together is the Red Hill Syenite. Foid, a contraction of the term ''feldspathoid'', is applied to any igneous rock containing up to 60% modal feldspathoid minerals. For example, a syenite with significant nepheline present can be termed a ''nepheline-bearing syenite'' or ''nepheline syenite'', with the term ''nepheline'' replaceable by any foid mineral. Such terminology is used in the Streckeisen ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feldspar
Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust and 41% of the Earth's continental crust by weight. Feldspars crystallize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Etymology The name ''feldspar'' derives from the German , a compound of the words ' ("field") and ("flake"). had long been used as the word for "a rock easily cleaved into flakes"; was introduced in the 18th century as a more specific term, referring perhaps to its comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidote Group
Epidotes are a group of sorosilicate minerals that are common in 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 ... and metamorphic rocks. Epidote member species *Clinozoisite, * Epidote, * Epidote-(Sr), * Hancockite, * Heflikite, * Mukhinite, * Niigataite, * Piemontite, * Piemontite-(Pb), * Piemontite-(Sr), * Tweddillite, References {{Reflist Calcium minerals Aluminium minerals Iron(III) minerals Epidote group Monoclinic minerals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
