In this article, starting with the depiction of the crystal structure, the relationship between the crystallization habit of the synthetic quartz and the physical and chemical conditions for its growth is described. The author puts forward a viewpoint that the simple form of the trigonal trapezohedron plays an important role during the growing period. By means of analysing the crystallization habit, an outer to inner relation between the external and the internal structures of the synthetic quartz has been established. Moreover, a correlation between the crystallization habit of the trigonal trapezohedron and the crystal defects has been studied for various seed orientations, namely the Z-cut, Y-cut, X-cut and the cut which intersects the Z-axis at 55°. The results of the experimental investigations show that the defects of synthetic quartz, usually called "facet defects", arise mainly from the growth traces of the crystal faces of the trigonal trapezohedron, while in the X-cut and Y-cut crystals there are still pyramidal growth interface defects formed between the various crystal faces concerned.
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