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In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid) is a solid that lacks the long-range order that is a characteristic of a crystal. The terms " glass " and "glassy solid" are sometimes used synonymously with amorphous solid; however, these terms refer specifically to amorphous materials that ...
A mineraloid is a naturally occurring substance that resembles a mineral, but does not demonstrate the crystallinity of a mineral. Mineraloid substances possess chemical compositions that vary beyond the generally accepted ranges for specific minerals, for example, obsidian is an amorphous glass and not a true crystal; lignite is derived from the decay of wood under extreme pressure ...
A crystal's crystallographic forms are sets of possible faces of the crystal that are related by one of the symmetries of the crystal. For example, crystals of galena often take the shape of cubes, and the six faces of the cube belong to a crystallographic form that displays one of the symmetries of the isometric crystal system. Galena also ...
Amethyst crystals – a purple quartz Apophyllite crystals sitting right beside a cluster of peachy bowtie stilbite Aquamarine variety of beryl with tourmaline on orthoclase Arsenopyrite from Hidalgo del Parral, Chihuahua, Mexico Aurichalcite needles spraying out within a protected pocket lined by bladed calcite crystals Austinite from the Ojuela Mine, Mapimí, Durango, Mexico Ametrine ...
BaTiO 3 single crystals [111] neutral (domain size of 60 ľm) d 33 = 241 ε 33 = 1959 k 33 = 55.9 Zgonik et al. 1994 [12] BaTiO 3 single crystals [111] (domain size of 22 ľm) d 33 = 256 ε 33 = 2008 k 33 = 64.7 Zgonik et al. 1994 [12] BaTiO 3 single crystals [111] neutral (domain size of 15 ľm) d 33 = 274 ε 33 = 2853 k 33 = 66.1 Zgonik et al ...
[15] [17] Other examples include layered crystals with variable layer stacking, or crystals that differ only in the regular arrangement of vacancies and substitutions. On the other hand, some substances that have a continuous series of compositions, may be arbitrarily split into several minerals.
Amorphous metals are either non-ferromagnetic, if they are composed of Ln, Mg, Zr, Ti, Pd, Ca, Cu, Pt and Au, or ferromagnetic, if they are composed of Fe, Co, and Ni. [24] Thermal conductivity is lower than in crystalline metals. As formation of amorphous structure relies on fast cooling, this limits the thickness of amorphous structures.
All crystals have translational symmetry in three directions, but some have other symmetry elements as well. For example, rotating the crystal 180° about a certain axis may result in an atomic configuration that is identical to the original configuration; the crystal has twofold rotational symmetry about this axis.