Paulingite | |
---|---|
General | |
Category | Zeolite Group |
Formula (repeating unit) | (K,Na,Ca) 3–4(Si,Al) 21O 42•17-22H 2O |
IMA symbol | Pau [1] |
Strunz classification | 9.GC.35 |
Crystal system | Cubic |
Crystal class | Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m) |
Space group | Im3m |
Identification | |
Color | Colorless, light yellow, orange, red |
Crystal habit | Typically as euhedral crystals |
Cleavage | None |
Fracture | Conchoidal |
Mohs scale hardness | 5 |
Luster | Vitreous to adamantine |
Diaphaneity | Transparent |
Specific gravity | 2.085 – 2.24 |
Refractive index | n = 1.472–1.484 |
Ultraviolet fluorescence | None |
References | [2] [3] [4] [5] |
Paulingite or paulingite-K is a rare zeolite mineral that is found in vesicles in the basaltic rocks from the Columbia River near Rock Island Dam, Washington.
Paulingite was named for Linus Carl Pauling (1901–1994), professor of chemistry, California Institute of Technology and accepted by the International Mineralogical Association in 1960. [4]
The early formation in the crystallization sequence and the high water content suggest that paulingite forms from relatively dilute pore fluids. They have a large unit cell of 3.51 nanometers and an isometric crystal system. This is the largest known inorganic unit cell apart from protein structures.[ citation needed ] Paulingite's characteristic structure can be observed while the remaining water content decomposes. A single crystal X-ray refinement of this chemically different sample material derived three main cation positions, which are inside a so-called paulingite or calcium (Ca), between 8-rings of neighbouring barium (Ba), and in the centre of the non-planar 8-rings of the -cage potassium (K).
This section may be confusing or unclear to readers. In particular, highly technical, grammatically erratic.(December 2018) |
Kamb and Oke in 1960 first described paulingite from vesicles in the Tertiary, augite-bearing, basaltic rocks at the Rock Island dam in Washington, where it is associated with clinoptilolite (Na,K,Ca)
2–3Al
3(Al,Si)
2Si
13O
36·12H
2O), phillipsite (Ca,Na2,K2)3Al6Si10O32·12H2O, calcite (CaCO3), and pyrite (FeS2). Zeolite minerals are crystalline, hydrated aluminosilicate of alkali and alkaline cations with a three-dimensional structure. It is a special group of minerals that is important due to its members' uses in different industries. Due to its special properties like attractive adsorption, cation-exchange, dehydration-rehydration and catalysis properties they are used in the nuclear industry, construction industry, agricultural industry, medical industry, petrochemical industry, space industry and domestic products industry (Fredrick A. Mumpton, 1998). It is a rare zeolite mineral with a dodecahedron crystal form {110} and has a very large unit cell with a = 3.51 nanometers. The mineral information was described by Kamb and Oke (1960) which has Si/Al ratio of 3.0, a BaO range of 0.5–4.1% and 18.5% of water content (Tscherinch and Wise, 1982).
Paulingite is a perfect clear rhombic dodecahedron of 0.1 to 1.0 mm in diameter. Their attachment to vesicles causes a hemispherical shape exhibiting 5 to 6 planes of dodecahedral planes. In the vesicular walls, they appear to be dark brown to black. They are actually clear and colorless due to clarity and their attachment to the vesicular wall. The crystal faces are smooth and planar and have a bright vitreous luster. The crystals have no cleavage. Under a binocular microscope, it resembles chips of ice. Lamellae seen optically may indicate twinning. They have a conchoidal fracture. It has a white streak. Rhombic dodecahedron is the dominant crystal form for paulingite. The hardness of paulingite is 5. The size of the paulingite unit cell is outstanding because it is the largest inorganic compounds exceeding most complex, intermetallic compounds. The measured density is 2.085 g/cm3 and calculated density is 2.10 g/cm3. The figure below shows the dodecahedron shape of paulingite mineral.
Viewing under a petrographic microscope, the crystals contains a scattering of minute bubble-like inclusions. Paulingite is mostly isotropic and in extreme cases that faint, isolated, fuzzy and weak birefringent twinning which is a determining factor for differentiating paulingite from analcite (NaAlSi2O6·H2O). The refractive index at 230 in sodium vapor light by immersion method is 1.473. Single crystal diffraction study provides information that paulingite is cubic and the cubic length of a0 = 35.10 Å. It was determined from rotation photograph using copper Ka radiation, nickel filtered, with the film in self-calibrating arrangement. The reflections were indexed with the help of a zero-layer Weissenberg photograph. Reflections of the type hkl for l = 0 to l = 12 have been examined with equi-inclination weissenberg photographs, and only reflections having h+k+l even are observed, indicating a body-centered lattice. The crystal system is isometric. The space group of the paulingite is Im3m and the point group is 4/m3 2/m (Kamb and Oke 1960).
Paulingite is usually found in vesicles of basalt flows. Because of its rarity, certain chemical factors have to be considered for its formation. The exchangeable cations do not control the formation of paulingite because variations of localities have different percentages to elements; e.g. Riggins zeolites are K rich while Chase Creek is Barium rich. The Si/Al ratio does not control the formation because the ratio is controlled by the pH of the solution. They may have formed around hydrated or partially hydrated alkali and alkaline earth cations which act as a template. Relatively low-saline solutions promote paulingite framework. So it occurs in sub-alkaline rocks. There are following localities where paulingite are also found which include Riggins in Idaho country, Ritter in Grant county and Chase creek in British Columbia. In Europe, Paulingite was found among zeolites of the Giants Causeway in Ireland and two zeolite localities near Howeneeg and Vogelsberg (Tscherinch and Wise, 1982).
In the US, at Rock Island Dam, on the Columbia River, Wenatchee, Douglas Co., Washington; from near Riggins, Idaho Co., Idaho; and at Three Mile Creek, near Ritter, Grant Co., Oregon. On Chase Creek, at the junction with Charcoal Creek, north of Falkland, British Columbia, Canada. Large crystals from the Giant's Causeway and Craigahulliar, Portrush, Co. Antrim, Northern Ireland. At Kladno and Vinarice, Czech Republic. In the Höwenegg quarry, Hegau, Baden-Württemberg, and in the Ortenberg quarry, Vogelsberg, Hesse, Germany.
Zeolite mineral species, pyrite and calcite are the important minerals are usually found in association with paulingite.
Analcime (; from Ancient Greek ἀνάλκιμος (análkimos) 'not strong') or analcite is a white, gray, or colorless tectosilicate mineral. Analcime consists of hydrated sodium aluminium silicate in cubic crystalline form. Its chemical formula is NaAlSi2O6 · H2O. Minor amounts of potassium and calcium substitute for sodium. A silver-bearing synthetic variety also exists (Ag-analcite). Analcime is usually classified as a zeolite mineral, but structurally and chemically it is more similar to the feldspathoids. Analcime is not classified as an isometric crystal, as although the crystal structure appears to be isometric, it is usually off only by a fraction of an angle. However, there are truly isometric samples of the mineral, which makes its classification even more difficult. Due to the differences between the samples being too slight, there's no merit from having multiple species names, so as a result analcime is a common example for minerals occurring in multiple crystal systems and space groups. It was first described by French geologist Déodat de Dolomieu, who called it zéolithe dure, meaning hard zeolite. It was found in lava in Cyclops, Italy. The mineral is IMA approved, and had been grandfathered, meaning the name analcime is believed to refer to a valid species til this day.
In geometry, a dodecahedron or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.
The mineral pyrite ( PY-ryte), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral.
Strontianite (SrCO3) is an important raw material for the extraction of strontium. It is a rare carbonate mineral and one of only a few strontium minerals. It is a member of the aragonite group.
Zeolite is a family of several microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula Mn+
1/n(AlO
2)−
(SiO
2)
x・yH
2O where Mn+
1/n is either a metal ion or H+. These positive ions can be exchanged for others in a contacting electrolyte solution. H+
exchanged zeolites are particularly useful as solid acid catalysts.
Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named:
In geometry, the rhombic dodecahedron is a convex polyhedron with 12 congruent rhombic faces. It has 24 edges, and 14 vertices of 2 types. It is a Catalan solid, and the dual polyhedron of the cuboctahedron.
Chabazite is a tectosilicate mineral of the zeolite group, closely related to gmelinite, with the chemical formula (Ca,K
2,Na
2,Mg)Al
2Si
4O
12•6H
2O. Recognized varieties include Chabazite-Ca, Chabazite-K, Chabazite-Na, and Chabazite-Sr, depending on the prominence of the indicated cation.
Torbernite, also known as chalcolite, is a relatively common mineral with the chemical formula Cu[(UO2)(PO4)]2(H2O)12. It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a secondary mineral. The chemical formula of torbernite is similar to that of autunite in which a Cu2+ cation replaces a Ca2+ cation. Torbernite tends to dehydrate to metatorbernite with the sum formula Cu[(UO2)(PO4)]2(H2O)8.
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula Na2Al2Si3O10·2H2O. The type locality is Hohentwiel, Hegau, Germany.
Scolecite is a tectosilicate mineral belonging to the zeolite group; it is a hydrated calcium silicate, CaAl2Si3O10·3H2O. Only minor amounts of sodium and traces of potassium substitute for calcium. There is an absence of barium, strontium, iron and magnesium. Scolecite is isostructural (having the same structure) with the sodium-calcium zeolite mesolite and the sodium zeolite natrolite, but it does not form a continuous chemical series with either of them. It was described in 1813, and named from the Greek word, σκώληξ (sko-lecks) = "worm" because of its reaction to the blowpipe flame.
Heulandite is the name of a series of tecto-silicate minerals of the zeolite group. Prior to 1997, heulandite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named:
Mordenite is a zeolite mineral with the chemical formula, (Ca, Na2, K2)Al2Si10O24·7H2O. and it is one of the six most abundant zeolites and is used commercially.
Gmelinite-Na is one of the rarer zeolites but the most common member of the gmelinite series, gmelinite-Ca, gmelinite-K and gmelinite-Na. It is closely related to the very similar mineral chabazite. Gmelinite was named as a single species in 1825 after Christian Gottlob Gmelin (1792–1860) professor of chemistry and mineralogist from Tübingen, Germany, and in 1997 it was raised to the status of a series.
Gmelinite-Na has been synthesised from Na-bearing aluminosilicate gels. The naturally occurring mineral forms striking crystals, shallow, six sided double pyramids, which can be colorless, white, pale yellow, greenish, orange, pink, and red. They have been compared to an angular flying saucer.
Laumontite is a mineral, one of the zeolite group. Its molecular formula is Ca(AlSi2O6)2 · 4H2O, a hydrated calcium-aluminium silicate. Potassium or sodium may substitute for the calcium but only in very small amounts.
Celadonite is a mica group mineral, a phyllosilicate of potassium, iron in both oxidation states, aluminium and hydroxide with formula K(Mg,Fe2+
)(Fe3+
,Al)[Si
4O
10](OH)
2.
Clinoptilolite is a natural zeolite composed of a microporous arrangement of silica and alumina tetrahedra. It has the complex formula (Na,K,Ca)
2–3Al
3(Al,Si)
2Si
13O
36•12H
2O. It forms as white, green to reddish tabular monoclinic tectosilicate crystals with a Mohs hardness of 3.5 to 4 and a specific gravity of 2.1 to 2.2. It commonly occurs as a devitrification product of volcanic glass shards in tuff and as vesicle fillings in basalts, andesites and rhyolites. It was described in 1969 from an occurrence in the Barstow Formation, San Bernardino County, California. Sodium levels in clinoptilolite are generally higher than potassium levels, as is the case with the San Bernardino Barstow Formation, but there are sources that are potassium-rich and have minimal sodium.
Gyrolite, NaCa16(Si23Al)O60(OH)8·14H2O, is a rare silicate mineral (basic sodium calcium silicate hydrate: N-C-S-H, in cement chemist notation) belonging to the class of phyllosilicates. Gyrolite is also often associated with zeolites. It is most commonly found as spherical or radial formations in hydrothermally altered basalt and basaltic tuffs. These formations can be glassy, dull or fibrous in appearance.
Zeolites are found in several locations in southern and central Idaho.
Tacharanite is a calcium aluminium silicate hydrate (C-A-S-H) mineral of general chemical formula Ca12Al2Si18O33(OH)36 with some resemblance to the calcium silicate hydrate (C-S-H) mineral tobermorite. It is often found in mineral assemblage with zeolites and other hydrated calcium silicates.