Translational symmetry is firmly established as the key property characterizing the crystalline state of matter. This is founded in the successes of translational symmetry in explaining physical properties of crystalline compounds and Bragg reflections in their diffraction patterns, as well as in the many substances that possess periodic atomic structures. An alternative and perhaps better characterization of the crystalline state is by long-range order of the atomic structure. The past fifty years have seen a continuous increase of the awareness that long-range order can be achieved differently than by translational symmetry. Modulated crystals and composite crystals have atomic structures that can be described as variations on periodic structures, while quasicrystals differ from crystals with translational symmetry in a more fundamental way. This book presents the methods of structural analysis of incommensurately modulated crystals and incommensurate composite crystals <...>

The declaration of National Mineral Policy 2008, amendments to MMDR Act 2015, and recent reforms in mining legislation viz. MEMC Rules 2015, National Mineral Exploration Policy 2016, Mineral Auction Rules 2015, NMET Rules 2015, and Mineral Concession Rules 2016 etc. were primarily aimed at attracting private investment and the latest technology in the mineral sector, assurance of uniform lease period, dealing with low exploration expenditure and eliminating procedural delays.

For the last twenty years conferences concerning rare earth materials have been held in the U.S.A. every 18 to 24 months. In general these conferences have dealt with the science of these materials, and only one or two sessions (~10% of the papers) were concerned with industrial and commercial aspects.

Kaolin is a commercial term used to describe white clay composed essentially of kaolinite, Al&010(OH)g. The term is typically used to refer to both the raw clay and the refined commercial product. This manual describes the laboratory assessment of ‘non-plastic’ kaolin (sometimes known as china clay); plastic kaolinitic clays (or ball clay) are dealt with elsewhere in this series of manuals. Although originally valued for use in the manufacture of whiteware ceramics, the principal use of kaolin is now in the filling and coating of paper. The mineral is also used to a lesser extent as a filler in paint, rubber and plastics, as well as in a wide range of other applications. Kaolins are distinguished from other clays by whiteness, and fine, controllable particle size. It is generally necessary to process kaolin from the crude state in order to optimise these highly commercial properties <...>