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The action of crystal growth yields a crystalline solid whose atoms or molecules are close packed, with fixed positions in space relative to each other. The crystalline state of matter is characterized by a distinct structural rigidity and very high resistance to deformation (i.e. changes of shape and/or volume).
In addition, physical properties are often controlled by crystalline defects. The understanding of crystal structures is an important prerequisite for understanding crystallographic defects. Most materials do not occur as a single crystal, but are poly-crystalline in nature (they exist as an aggregate of small crystals with different orientations).
For example, on the International Space Station the Earth's gravity is nearly 90% as strong as at the surface. Objects orbiting in space would not remain in orbit if not for the gravitational force, and gravitational fields extend even into the depths of intergalactic space. [5] [6] [7] The dark side of the Moon illuminated by the Sun.
Chemical clues in zircon crystals suggest the rock in which they formed came into contact with fresh water 4 billion years ago, when Earth was thought to be covered in ocean.
1723 - Moritz Anton Cappeller introduced the term crystallography in his book Prodromus Crystallographiae De Crystallis Improprie Sic Dictis Commentarium. [3]1766 - Pierre-Joseph Macquer, in his Dictionnaire de Chymie, promoted mechanisms of crystallization based on the idea that crystals are composed of polyhedral molecules (primitive integrantes).
Crystals, though long admired for their regularity and symmetry, were not investigated scientifically until the 17th century. Johannes Kepler hypothesized in his work Strena seu de Nive Sexangula (A New Year's Gift of Hexagonal Snow) (1611) that the hexagonal symmetry of snowflake crystals was due to a regular packing of spherical water particles. [1]
Fractional crystallization, or crystal fractionation, is one of the most important geochemical and physical processes operating within crust and mantle of a rocky planetary body, such as the Earth. It is important in the formation of igneous rocks because it is one of the main processes of magmatic differentiation . [ 1 ]
Widmanstätten patterns, also known as Thomson structures, are figures of long phases of nickel–iron, found in the octahedrite shapes of iron meteorite crystals and some pallasites. Iron meteorites are very often formed from a single crystal of iron-nickel alloy, or sometimes a number of large crystals that may be many meters in size, and ...