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A text-book of mineralogy

TL;DR: A textbook of mineralogy as mentioned in this paper is a text-book of the mineralogy, which is used in many applications in the field of science and technology. But this textbook is not suitable for mining.
Abstract: A text-book of mineralogy , A text-book of mineralogy , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
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Journal ArticleDOI
01 Feb 2008-Geology
TL;DR: The trace element compositions of aplite dikes in the Sierra Nevada batholith of California differ profoundly from high-silica rhyolites (HSRs) and contradict a genetic connection to them as discussed by the authors.
Abstract: The trace element compositions of aplite dikes in the Sierra Nevada batholith of California differ profoundly from high-silica rhyolites (HSRs) and contradict a genetic connection to them. The aplites are strongly depleted in all middle rare earth elements (REEs), whereas HSRs are strongly depleted only in Eu and enriched in other REEs; the aplites are strongly depleted in Y and variably enriched in Sr, whereas HSRs are enriched in Y and strongly depleted in Sr. Volcanic rocks with the trace element characteristics of these aplites are rare to absent in the geologic record. Aplite REE patterns are likely controlled by titanite, which has large distribution coefficients for REEs, whereas HSRs cannot have equilibrated with titanite. Titanite may crystallize late in dacitic magma and thus HSR may be extracted before titanite saturation is reached; aplites would form after titanite appears, but when the melt percentage is too low and the water content of the melt too high (at fluid saturation) for the magma to ascend without rapid crystallization, thus preventing eruption. HSRs could also form by low-degree partial melting of granodiorite plutons in which titanite melts out early. Alternatively, HSRs may be extracted from silica-rich plutons that lack titanite; leucogranite plutons with REE contents that could be complementary to HSRs are present but uncommon in the Sierra Nevada.

166 citations

Journal ArticleDOI
TL;DR: An overview of the crystallography of aperiodic crystals, in particular of incommensurately modulated structures and intergrowth compounds, is given in this paper, where the symmetry, the description of the structure and diffraction are described.
Abstract: An overview is given of the crystallography of aperiodic crystals, in particular of incommensurately modulated structures and incommensurate intergrowth compounds. The symmetry, the description of the structure and diffraction are described. An extensive discussion is given of crystallographic methods for determination of incommensurate crystal structures. A series of specific compounds is discussed in detail, covering the various ways of incommensurateness. Special attention is given to the commensurate approximation and to the superspace description of superstructures. An historical introduction and a section on the relation between physical properties and incommensurate structure are included.

163 citations

Journal ArticleDOI
TL;DR: In this article, weak-oscillatory-zonation patterns are overprinted by secondary textural features characterized by mottled, convoluted and wavy internal zonation patterns that are frequently associated with secondary micron- to submicron-scale micro-porosity.

40 citations

01 Oct 2008
TL;DR: In this article, Kaolin clay from Deopani deposit of Assam contains high amount of iron and titanium-bearing minerals, which can be separated by wet high intensity magnetic separator Titaniferrous impurities present as coatings on kaolinite particles.
Abstract: Kaolin clay from Deopani deposit of Assam contains high amount of iron. Kaolinite particles, characterized by SEM-EDX, are pseudohexagonal and arranged in face-to-face pattern. Clay particles are coated with iron- and titanium-bearing minerals, which can be separated by wet high intensity magnetic separator Titaniferrous impurities present as coatings on kaolinite particles are difficult to remove by oxalic acid treatment.

25 citations