Morphology of crystals

The nucleation, growth, and morphology of crystals are influenced by both temperature and stress. 

Hartman, P. and Perdok, W.G., 1955. On the relations between structure and morphology of crystals. Acta Crystallogr., 8, 49. 

Procedure Prepare a saturated solution of inorganic salts in water and crystallize by keeping over ultrasonic bath for an hour or until the crystals just appear to form. Differentiate the morphology of crystals formed under normal and ultrasonic conditions under microscope. SEM pictures of some of such materials are being given here for comparison. 

Sunagawa, I. (1987 a) The morphology of minerals. In Sunagawa, I. (ed.) The morphology of crystals. Terra Sdentific Publ. Co., Tokyo, Japan, 509—588... 

In the nineteenth century, when crystal morphology was systematized to fourteen types of unit cells, seven crystal systems and thirty-two crystal groups, the following two macroscopic treatments on the morphology of crystals emerged. 

The aim of this book is to analyze phenomena in complicated and complex systems, such as crystallization in minerals and in the living world, using the morphology of crystals as the key. 

In Part I, after systematically summarizing the hitherto used terms in the morphology of crystals, we summarize the developments in the atomic process of crystal growth and morphology achieved in the twentieth century. 

The morphology of crystals is the central theme of this book. Our intention is to present systematically the fundamental concepts that allow us to analyze the factors that determine the various forms of crystals. We may then deduce and analyze the phenomena and processes that we cannot observe in situ, such as those occurring in the depths of the Earth or in the animate world. 

This is an important phenomenon in analyzing the morphology of crystals. 

As explained above, three fundamental models of crystal growth mechanism were established in relation to the roughness of interfaces these are illustrated in Fig. 3.14. At present, there is no other known growth mechanism that is essentially different from these three. Therefore, we shall analyze the morphology of crystals, the main topic of this book, based on these three growth mechanisms. 

Figure 3.21. Changes in the morphology of crystals, shown on a growth rate versus driving force diagram (see Fig. 3.15), assuming a crystal bounded by the 111) face only.

Figures 3.24(a) and (b) show morphodroms of silicate crystals growing from silicate solutions Fig. 3.24(a) shows the results of observations on quenched products, and Fig. 3.24(b) summarizes the results obtained by a high-temperature in situ observation method of growth [23]. In these cases also, as apart from the liquidus of solid-solution component, it is seen that the morphology of crystals changes from polyhedral, through hopper, to dendritic, then spherulitic. The predictions described in Section 3.12 are thus confirmed by experiment.

I. Sunagawa (ed.). Morphology of Crystals, Part C, Dordrecht, D. Reidel, 1994... 

The discussions summarized in Sections 4.4.2-4.4.S relate to the morphologies of crystals of size down to a few millimeters. Will extremely tiny crystals of sizes ranging from a few to 100 nm take polyhedral forms bounded by flat faces, or will they show forms bounded by curved faces due to the size effect It was theoretically predicted that, as the size of solid materials decreases, a change is expected to occur in the physical properties. Also, considering the presence of ultra-fine particles in the cosmos, the morphology exhibited by ultra-fine particles attracts a special concern. 

P. Bennema andj. P. van der Eerden, Crystal graphs, connected nets, roughening transition and the morphology of crystals, inMorphology of Crystals, Part A,... 

E. 1. Givargizov, Highly Anisotropic Crystals, Dordrecht, D. Reidel, 1986 1. Sunagawa (ed.j. Morphology of Crystals, Parts A and B, Dordrecht, D. Reidel, 1987 1. Sunagawa (ed.). Morphology of Crystals, Part C, Dordrecht, D. Reidel, 1994 1. Rostov and R. 1. Rostov, Crystal Habits of Minerals, Sofia, Professor Martin Drinov Academic Publishing House and Pensoft... 

Y. Aoki, Morphology of crystals grown from highly supersaturated solutions, Mem. Sci,... 

Ichiro Sunag awa is the Principal of the Yamanashi Institute of Gemmology and Jewellery Arts, and Emeritus Professor at Tohoku University. He has written or edited a number of books in English or Japanese, including Morphology of Crystals (1988) and Handbook of Crystal Growth (2000). His contribution to the scientific literature is considerable, with over 200 papers in English and more than 300 in Japanese. 

The more modern methods of predicting the morphologies of crystals are based on the calculation of the energies of the various faces. The methods are based on the intuitive consideration that the closed polyhedron describing the shape of the crystal is determined by the faces with the lowest surface free energy and that the extension of these faces is inversely proportional to the respective surface free energy. 

The change in morphology of crystals of zeolite omega has been analyzed with respect to the evolution of the concentration of aluminium in the parent liquor. In agreement with the overlapping principle, crystal habit is determined by the faces with the lowest growing rate. 

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