Silicates amphiboles

Spectra of chain silicates Amphibole group 5.6.1 Background... 

S5 Infinite double chains of tetrahedra (duochain silicates) amphibole family (Fig. 3E) (Si4On) 2 and 3 SiOiVl Tremolite (OH)2Ca2Mg5 Si8022... 

Asbestos and asbestiform silicates Amphibole asbestos, erionite > chrysotile asbestos... 

The bands are usually alternatingly light (quartz and feldspars) and dark (layer silicates, amphiboles, pyroxenes, garnet, etc.), and often display preferred orientation of mineral grains. Because metamorphic rocks display abundant field and petrographic evidence of deformation, metamorphic banding has always been attributed to stress or to the strain produced by it. 

S-Na2Sip6 700 2 20 Serpentine, NaMg-threechain silicate, amphibole, forsterite, enstatite, fluorides, ore mineral... 

Brantley, S. L. and Chen, Y. (1995). Chemical weathering rates of pyroxenes and amphiboles. In Chemical Weathering Rates of Silicate Minerals" (A. F. White and S. L. Brantley, eds), Mineralogical Society of America Washington, EXT, Reviews in Mineralogy 31,119-172. 

There are no noble gas partitioning data for amphiboles. Given the multiplicity of cation and anion sites in this mineral it seems likely that Uru will be higher than in other silicate minerals. 

A layer of tetrahedra can be considered as being built up by linking parallel chains. That this is not a mere formalism is shown by the existence of intermediate stages. Two linked silicate chains result in a ribbon of the composition [Si4Of ] it has two kinds of tetrahedra, one kind being joined via three and the other kind via two vertices, [SiO Oj SiOj/jOj ]3 Silicates of this type are termed amphiboles. They are fibrous and also used to be used as asbestos. 

In studies of amphiboles (44), isolated strips of triplechain silicates were discovered embedded in the double-chain parent structure. It was later realized that new types of silicate structures, composed of recurrent triple chains, existed in nature. The part that HREM played in the identification of this new family of triple-chain silicates, which constitute a further step in the progression pyroxene, amphibole,. .. mica, was crucial. 

Amperometric cells, sensors using, 22 271 Amperometric measurements, 14 612 Amphetamine, 3 89-90 Amphibole asbestos, 1 803 3 288 crystal structure, 3 297-298 exposure limits, 3 316 fiber morphology, 3 294-295 silicate backbone, 3 296 Amphibole potassium fluorrichterite, glass- ceramics based on, 12 637 Amphiphile-oil-water-electrolyte phase diagram, 16 427-428 Amphiphile-oil-water phase diagrams,... 

Similarly to Mn(IV)- and Fe(III)-oxides, some primary minerals were shown to promote polymerization of hydroquinone (19). Olivines, pyroxenes, and amphiboles accelerated the polymerization reaction to a greater extent than micas and feldspars. Microcline and quartz were ineffective- The effect was greatest for tephroite, a manganese-bearing silicate with the ideal chemical formula M SiO. Fayalite, the corresponding Fe(II) analog (Fe2Si0 ), was effective, but to a lesser extent. 

Table 10.2 Upper concentration limits for Henry s law behavior in silicates and oxides. Abbreviations Ab = albite Sa = sanidine PI = plagioclase Pel = alkaline feldspar Rb-fel = Rb-feldspar Ne = nepheline Mu = muscovite 01 = olivine Di = diopside Cpx = clinopyroxene Oxp = orthyporoxene Amph = amphibole Par = pargasite Gr = garnet Ilm = ilmenite ...

Ralston, J., and Kitchener, J. A. (1975). The surface chemistry of amosite asbestos, an amphibole silicate. J. Colloid Interface Sci. 50 242-249. 

Fig. 2.1 Configurations of the tetrahedral units and chain, double chain, and sheet structures in the silicate and aluminosilicate minerals. (A) Two-dimensional representation of a single silicate tetrahedron. (A ) Two-dimensional representation of an extended silicate chain. (B) Three-dimensional representations of single tetra-hedra in two orientations. The apexes of the tetrahedra point above or below the plane of the paper. (B ) Three-dimensional representations of extended silicate chains showing different orientations of the tetrahedra in two of the many possible configurations. Single chain pyroxenes (C), wollastonite (D), rhodonite (E). Double chains amphiboles (F). Sheets as found in the serpentines, micas, and clays (G).

Minerals and mineral series with the same basic chemical units, such as the silicate polymerized ions, and very similar crystal structures are related and referred to collectively as mineral groups. The amphiboles are a group composed of several mineral series, two of which were cited in the preceding examples. The several series that make up the amphibole group reflect the changes in the size and location of cations associated with the polymerized silicate chains. Because several amphibole species occur in fibrous fonn, we discuss this group in much greater detail, and include an idealized crystal structure. 

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