Albite, NaAlSi

Most igneous and metamorphic rocks are composed predominantly of alurninosiHcate minerals, including feldspar such as albite (NaAlSi Og) or anorthite (CaAl2Si20g) and crystalline forms of siHca such as quartz (Si02). Various mixed metal-plus-siHcon oxides such as oHvine [(Mg,Fe)2(SiO ] and... 

A recent innovation in thin-film detectors has appeared on the commercial market in which a standard Si(Li) detector is protected by an apparently strong, X-ray transparent and radiation insensitive thin-film. The exact nature and composition of this thin-film is yet to be disclosed in the open literature. However, according to manufacturer s reports [13] this detector window allows transmission of boron X-rays (0.185kv for Ka) and can be operated at atmospheric pressure. In a typical spectrum from this type of detector provided by the manufacturer, a strong oxygen Ka line as well as well-defined Si, Al and Na peaks can be observed for albite (NaAlSi Og). Since these detectors have only recently been installed in the field, details of performance have yet to be reported by users. 

Figure 3.14. spectra at 7.05 T from crystalline albite (NaAlSi Og) as the spinning speed is increased from 0 to 10 kHz showing the distortion at low spinning speed from Smith and van Eck (1999) with permission of the copyright owner. 

The most reactive metals, such as sodirun and potassium, are present in nature as soluble salts in the ocean and mineral springs in solid deposits of these salts or in insoluble, stable aluminosilicates, such as albite (NaAlSi Og) and orthoclase (KAlSijOg). Such silicates are found in aU parts of the world, but because of their great stability they are not currently used as sources of the metals they contain. These minerals, like the ocean, represent a resource that may have to be tapped when richer and more easily processed ores are depleted. 

NaAl2(AlSig0 Q)(0H)2+ SiOg = NaAlSi Og+ AlgSiO + HgO (28). paragonite quartz albite andalusite steam... 

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