Home Contact. Crystal Structure Determination This textbook provides a concise introduction to modern crystal structure determination, emphasizing both the crystallographic background and the successive practical steps. In the theoretical sections, more importance is attached to a good understanding, assisted by many figures, than to a rigorous mathematical treatment.
The most important measuring techniques, including the use of modern area detectors, and the methods of data reduction, structure solution and refinement are discussed from a practical point of view. A special emphasis is put on the ability to recognize and avoid possible errors and traps, and to judge the quality of results.
Crystal Identification With The Polarizing Microscope This text describes the theory and practice of optical mineralogy in terms useful to all practitioners from the beginning student to the professional in field and laboratory geology and industrial and environmental mineralogy.
The author's aim is to provide the simplest possible access to the most powerful techniques of optical crystal identification. The book emphasizes useful practical theoretical material and methods for studying both thin sections of rocks and immersion of mineral grains in refractive index liquids. It contains original research results found in no other text. A major goal of the text is to allow precise determination of refractive index and the essential composition of crystals belonging to important mineral groups such as olivine, feldspar, and pyroxene.
New methods for achieving this are developed for both white light and colored light of variable wavelength. Among the book's unique features is the color fringe chart developed by Prof. Morse for estimating both the direction and degree of mismatch between the refraction index of a crystal and that of the surrounding liquid medium in the immersion method.
Some other reactions, which are referred to as metasomatic, are induced by the reverse effect, i. A metasomatic process can be a priori supposed to encompass similar to the processes of direct growth a wide variety of phenomena, which arise from a vast diversity of combinations of subelementary processes. It is suggested that polymineral-metasomatic processes should be classified according to their degree of spatiotemporal correlation between growth and dissolution.
Qualitative attributes of the correlation make it possible to single out four overelementary classes; correlation in the first class is maximal, while in the fourth one it is minimal. Dissolution and growth occur within a single crystal grain and take place synchronously. Secondary formations preserve a considerable part of structuralmorphological information about a protocrystal.
Characteristic features of the secondary crystals indicating causeeffect relationships between growth and dissolution are concealed by inherited attributes of the initial crystals. This class also includes a unique process of monocrystal isomorphic replacement.
Every moment in the course of this replacement, growth, and dissolution microsites covering the protocrystal relic and the relic itself form a mosaic-heterogeneous monocrystal. The problem of structure and genesis of isomorphic monocrystalline pseudomorphs was solved for the first time ever. The mechanism of isomorphic component selection by a growing crystal is established as a consequence of action of metasomatic component during a mixed crystal formation. Crystals undergoing dissolution and growth are separated from each other by some volumes of solution, but dissolution and growth are unambiguously coordinated with each other in space and proceed almost simultaneously.
Secondary formations preserve sufficient structural-morphological information about a protocrystal. Characteristic features of the secondary crystals and aggregates indicating causeeffect relationships between growth and dissolution are extremely distinct. This class comprises a majority of polycrystalline and negative products of replacement of monocrystals see Sect.
We observed formation of both pseudomorphs and new replacement products, e.
Our genetic classification is based on the principle of disappearance of information about a protocrystal and encompasses known and possibly existing structural-morphological types. There were synthesized case-like aggregates and combined products, i. All main types and factors of replacement were provided with reliable genetic interpretations.
Structure of replacement products is defined by a physicochemical type of a system. Degree of the product inheriting the protocrystal contours depends upon the nature of kinetic constituents of replacement process. Ratio of component solubilities calculated from the phase diagrams defines a volume effect of the replacement, which is one of the most. Quantitative ratios between dissolving and precipitating components are defined by salting-in and salting-out mechanisms.
Dissolution and growth are not coordinated with each other in space, but proceed more or less simultaneously. Secondary formations lose a sufficient part of structural-morphological information about a protocrystal or initial structure of aggregate. Characteristic features of secondary crystals and aggregates characterizing causeeffect relationships between growth and dissolution are dissipated.
This class includes such type of monocrystal replacement as formation of dissipated automorphs see Sect. However, the most numerous group includes replacements of aggregates. Naturally occurring aggregates and rocks are highly diversified in their mineral compositions and primary structures that make the number of their possible forms and combinations practically uncountable.
The present monograph discusses some principal attributes of interaction between the products obtained via replacement of an ensemble of individuals see Sect. A model for formation of rapakivi granites, which are considered here as products of replacement of feldspar rocks see Sect. Dissolution and growth are not spatially coordinated and are asynchronous. Secondary formations lose any information about a protocrystal or initial structure of aggregate or acquire false information.
Characteristic features of secondary crystals and aggregates characterizing causeeffect relationships between growth and dissolution are absent. This class includes such type of monocrystal replacement as formation of translocated replacement products localized at random in respect to initial crystals see Sect. The most numerous group includes processes of recrystallizations in solutions.
Our experimental investigations revealed principle regularities of layering and transformation of grain sizes in polymineral aggregates in fluctuating temperature modes or at temperature gradients see Sect. Under temperature fluctuation conditions, two main factors acting simultaneously define the process: the first factor is temperature fluctuations or fluctuations of other intensive parameters , while the second factor is heterogeneity of an aggregate caused by structural differences of its composing individuals and their various degrees of imperfection.
Aggregates can be divided into passive and active depending upon the properties of the physicochemical systems, i. The process becomes stationary at its final stage and the aggregate structure does not undergo any changes.
A particular case of the suggested model is recrystallization of monomineral aggregates proceeding as a sequence of alternating acts of growth and dissolution of crystals having various degrees of imperfection. It should be noted that only a borderline between the first and second classes is definite enough, while the other boundary criteria are not too distinct.
Imprecision of the outer border of the first class is a result of concealing attributes of isomorphic monocrystalline replacement by full information about the protocrystal, which is inherited by the replacement products. On the contrary, imprecision. Therefore, classification of any particular phenomenon can be changed after the phenomenon has been thoroughly investigated. Thus, direct growth of isomorphic-mixed crystals was previously referred to as a subelementary process; later it was found to involve a metasomatic component and consequently regarded as a first overelementary class phenomenon.
Mixed processes mentioned above, which are some combinations of direct growth or direct dissolution and metasomatic replacement, also affect the whole crystallogenesis picture. Moreover, complex equilibria in multicomponent systems cause a nonmonotonous character of the phase diagrams and in an inadequacy of supersaturation and supercooling or undersaturation and overheating. As a whole, all observed overelementary-level effects, as well as subelementary phenomena including oriented growth and faceting of crystals, can be interpreted from a conventional crystallogenetic point of view, which should be widened to include all necessary concepts concerning physicochemical nature of the process and combinations of growth and dissolution.
It should be emphasized that for many decades numerous investigators have accumulated vast experimental and naturally obtained data concerning compositions, crystal structures, morphology, and spatiotemporal correlations between synthesized and natural products. Nevertheless, those vast data do not include all possible products and they lack any unifying systematization or generalized genetic scheme. Classification criterion of synchronousasynchronous growth and dissolution was introduced by A.
Polymineral-Metasomatic Crystallogenesis is dedicated to the foundations of polymineral crystallogenesis in solutions typically occurring in nature. Effects, laws. "Polymineral-Metasomatic Crystallogenesis" is dedicated to the foundations of polymineral crystallogenesis in solutions typically occurring in nature. Effects.
Zhabin and V. Rusinov in , but it has not been modified to suit various types of replacement products and does not take into account spatial correlations of elementary processes. Diffusioninfiltration theory of matter redistribution in metasomatic columns, which has been developed by D. Korzhinskii and his scientific group since s, does not take into consideration behavior of primary and secondary crystalline material. Numerous mismatching interpretations of metasomatic phenomena result in conclusion about its totally paradoxical nature made by G. Pospelov in To resolve the contradictions an unrealistic assumption has been introduced about the particular nature of chemical reactions taking place in the earth crust expressed from time to time by some scientists for instance by N.
Nakovnik in , D.
Grigorev in , and E. Lazarenko in Poorly developed basis of physicochemical and crystallogenetic concepts describing processes proceeding in polymineral media determines preference of intuition genetic interpretations of morphological-crystallochemical properties of minerals and structure texture peculiarities of aggregates that results in ambiguous or false conclusions. The purpose of the presented monograph is to facilitate development of fundamental crystallogenesis and improve efficiency of studying the natural mineral formation. Numerous descriptions of natural products of metasomatic replacement and their interactions with initial minerals protocrystals; they can be also referred to as educts Nakovnik cannot provide a consistent overview of regularities and mechanisms of the process.
However, they do allow to state that no prior limitations could be imposed upon the product composition and structure and extent of its inheriting the educt form. Apparently, a majority of minerals can be exposed to replacement. Certain pairs educt product are widely distributed pyrite ferrous hydroxides, orthoclase kaolinite, calcite quartz.
However, even more diversified kinds of replacements were observed, which included such exotic examples as magnetite talc Dr. Levitskiis collection, private communication, and aragonite copper Amstutz a. Analysis of crystal grain replacement products shows that they can be both monomineral, such as malachite pseudomorphs formed after azurite Amstutz b , which is in good agreement with the concept of simplifying a mineral composition of the rock under metasomatic conditions Korzhinskii , , and others , and polymineral, such as achtarandite Lyakhovich ; Kleber and Pascal ; Galuskin et al.
Most natural formations unambiguously identified as products of metasomatic replacement are polycrystalline pseudomorphs of mineral individuals.
Shaped crystal growth Genetic model of rapakivi-type structures 5. Symposium on molecular-beam epitaxy ; Moscou. We can easily read books on the mobile, tablets and Kindle, etc. We moved your item s to Saved for Later. It is being developed at Indian Institute of Technology Kharagpur. Ebooks and eBook readers provide substantial benefits over traditional reading.
The first description of pseudomorphs and the term itself belonged to R. Hay The first register of different pseudomorphs occurring in the mineral environment was issued as early as in the middle of the nineteenth century Blm , and this work has not lost its significance until now.