|
Johnsenite-(Ce)
Johnsenite-(Ce) is a very rare mineral of the eudialyte group,Mindat, Johnsenite-(Ce), http://www.mindat.org/min-27479.html with the chemical formula .Grice, J.D., and Gault, R.A., 2006. Johnsenite-(Ce): a new member of the eudialyte group from Mont-Saint Hilaire, Quebec, Canada. The Canadian Mineralogist 44, 105–115 The original formula was extended to show the presence of both the cyclic silicate groups and silicon at the M4 site, according to the nomenclature of the eudialyte group.Johnsen, O., Ferraris, G., Gault, R.A., Grice, D.G., Kampf, A.R., and Pekov, I.V., 2003. The nomenclature of eudialyte-group minerals. The Canadian Mineralogist 41, 785–794 It is the third eudialyte-group mineral with essential tungsten (after khomyakovite and manganokhomyakovite), and second with essential rare earth elements (after zirsilite-(Ce), which is the niobium-analogue of johnsenite-(Ce)). In fact, some niobium substitutes for tungsten in johnsenite-(Ce). Other characteristic feature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eudialyte Group
Eudialyte group is a group of complex trigonal zircono- and, more rarely, titanosilicate minerals with general formula (1)N(2)N(3)N(4)N(5)sub>3 (1a)M(1b)sub>3M(2)3M(4)Z3 i24O72'4X2, where N(1) and N(2) and N(3) and N(5) = Na+ and more rarely H3O+ or H2O, N(4) = Na+, Sr2+, Mn2+ and more rarely H3O+ or H2O or K+ or Ca2+ or REE3+ (rare earth elements), M(1) and M(1b) = Ca2+, M(1a) = Ca2+ or Mn2+ or Fe2+, M(2) = Fe (both II and III), Mn and rarely Na+, K+ or Zr4+, M(3) = Si, Nb and rarely W, Ti and [] (vacancy defect, vacancy), M(4) = Si and or rarely [], Z Zr4+ and or rarely Ti4+, and X = OH−, Cl− and more rarely CO32− or F−. Some of the eudialyte-like structures can even be more complex, however, in general, its typical feature is the presence of i3O9sup>6− and i9O27sup>18− ring silicate groups. Space group is usually ''R''3''m'' or ''R''-3''m'' but may be reduced to ''R''3 due to cation ordering. Like other zirconosilicates, the eudialyte group minerals pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclosilicate
Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, the crystalline forms of silica (silicon dioxide, ) are usually considered to be Silicate mineral#Tectosilicates, tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz, and its polymorphism (materials science), polymorphs. On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis. Living organisms also contribute to this carbonate–silicate cycle, geologic cycle. For example, a type of plankton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrrhotite
Pyrrhotite (''Pyrrhus of Epirus, pyrrhos'' in Greek language, Greek meaning "flame-coloured"'')'' is an iron sulfide mineral with the formula Fe(1−x)S (x = 0 to 0.125). It is a nonstoichiometric compound, nonstoichiometric variant of FeS, the mineral known as troilite. Pyrrhotite is also called magnetic pyrite, because the color is similar to pyrite and it is weakly magnetic. The magnetism decreases as the iron content increases, and troilite is non-magnetic. Pyrrhotite is generally tabular and brassy/bronze in color with a Lustre (mineralogy), metallic luster. The mineral occurs with Mafic, mafic igneous rocks like Norite, norites, and may form from pyrite during Metamorphism, metamorphic processes. Pyrrhotite is associated and mined with other sulfide minerals like pentlandite, pyrite, chalcopyrite, and magnetite, and has been found globally. Structure Pyrrhotite exists as a number of polytypes of Hexagonal crystal system, hexagonal or monoclinic crystal symmetry; sever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrite
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of ''fool's gold''. The color has also led to the nicknames ''brass'', ''brazzle'', and ''brazil'', primarily used to refer to pyrite found in coal. The name ''pyrite'' is derived from the Greek (), 'stone or mineral which strikes fire', in turn from (), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what is now called pyrite. By Georgius Agricola's time, , the term had become a generic term for all of the sulfide minerals. Pyrite is usually found associated with other sulfides or oxides in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pectolite
Pectolite is a white to gray mineral, Na Ca2 Si3 O8(O H), a sodium calcium hydroxide inosilicate. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. It has a Mohs hardness of 4.5 to 5 and a specific gravity of 2.7 to 2.9. A highly sought-after variety known as larimar, is a pale to sky blue. There is also a whitish form of the mineral from Alaska that is sometimes marketed as 'Alaska jade'. Occurrence It was first described in 1828 at Mount Baldo, Trento Province, Italy, and named from the Greek ''pektos'' – "compacted" and ''lithos'' – "stone". It occurs as a primary mineral in nepheline syenites, within hydrothermal cavities in basalts and diabase and in serpentinites in association with zeolites, datolite, prehnite, calcite and serpentine. It is found in a wide variety of worldwide locations. See also *Serandite Serandite is a mineral with formula Na(Mn2+,Ca)2Si3O8(OH). The mineral was discovered in Guinea in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natrolite
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klaproth in 1803. The name is derived from ''natron'' (), the Greek word for soda, in reference to the sodium content, and ''lithos'' (), meaning stone. Needle stone or needle-zeolite are other informal names, alluding to the common acicular habit of the crystals, which are often very slender and are aggregated in divergent tufts. The crystals are frequently epitaxial overgrowths of natrolite, mesolite, and gonnardite in various orders. Properties Larger crystals most commonly have the form of a square prism terminated by a low pyramid, the prism angle being nearly a right angle. The crystals are tetragonal in appearance, though actually orthorhombic. There are perfect cleavages parallel to the faces of the prism. The mineral also often o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms. The Mo-S bonds are strong, but the interaction between the sulfur atoms at the top and bottom of separate sandwich-like tri-layers is weak, resulting in easy slippage as well as cleavage planes. Molybdenite crystallizes in the hexagonal crystal system as the common polytype 2H and also in the trigonal system as the 3R polytype. Description Occurrence Molybdenite occurs in high temperature hydrothermal ore deposits. Its associated minerals include pyrite, chalcopyrite, quartz, anhydrite, fluorite, and scheelite. Important deposits include the disseminated porphyry molybdenum deposits at Questa, New Mexico and the Henderson and Climax mines in Colorado. Molybdenite also occurs in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcline
Microcline (KAlSi3O8) is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow cooling of orthoclase; it is more stable at lower temperatures than orthoclase. Sanidine is a polymorph of alkali feldspar stable at yet higher temperature. Microcline may be clear, white, pale-yellow, brick-red, or green; it is generally characterized by cross-hatch twinning that forms as a result of the transformation of monoclinic orthoclase into triclinic microcline. The chemical compound name is potassium aluminium silicate, and it is known as E number reference E555. Geology Microcline may be chemically the same as monoclinic orthoclase, but because it belongs to the triclinic crystal system, the prism angle is slightly less than right angles; hence the name "microcline" from the Greek "small slope". It is a fully ordered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galena
Galena, also called lead glance, is the natural mineral form of lead(II) sulfide (PbS). It is the most important ore of lead and an important source of silver. Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the Cubic (crystal system), cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite. As a pure specimen held in the hand, under standard temperature and pressure, galena is insoluble in water and so is almost non-toxic. Handling galena under these specific conditions (such as in a museum or as part of geology instruction) poses practically no risk; however, as lead(II) sulfide is reasonably reactive in a variety of environments, it can be highly toxic if swallowed or inhaled, particularly under prolonged or repeated exposure. Occurrence Galena is the main ore of lead, used since ancient times, since lead can be smelted from galena in an ordinary wood fire. G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluorapophyllite
Fluorapophyllite-(K), formerly known as apophyllite-(KF) and sometimes simply referred to as fluorapophyllite, is the most common mineral of the apophyllite group, with the chemical formula of KCa4Si8O20(F,OH)·8(H2O). It gets the first part of its name, "fluor", because it contains more fluorine than hydroxide compared to the other minerals in the apophyllite group. Fluorapophyllite crystallizes in the tetragonal crystal system. Tetragonal minerals have three axes of different lengths and angles of 90 degrees. Fluorapophyllite is an anisotropic mineral and has low relief. This mineral belongs to the uniaxial (+) optical class, which means its indicatrix has a prolate sphenoid shape with a circular section, principal section, and one optic axis. Fluorapophyllite is popular among many mineral collectors because of the large, well-developed crystals they form and the multiple colors they come in. The most wanted variation of fluorapophyllite is the green colored variant, which is f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
