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An example of the tetragonal crystals, wulfenite Two different views (top down and from the side) of the unit cell of tP30-CrFe (σ-phase Frank–Kasper structure) that show its different side lengths, making this structure a member of the tetragonal crystal system. In crystallography, the tetragonal crystal system is one of the 7 crystal systems.
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It crystallizes in the tetragonal system, in the form of square tabular crystals, and with distinct cleavage on {011}. It crystals also display transparency and adamantine luster. The X-ray diffraction data, calculated cell dimensions, constants and optic axial angles of the synthetic wulfenite are consistent with those of the natural mineral.
Its crystals are in the tetragonal crystal system, appearing as dipyramidal pseudo-octahedra. Colors include golden yellow, brownish green to dark brown, pinkish to reddish gray, orange and colorless. Transparency ranges from translucent to transparent and crystal faces are highly lustrous (vitreous to adamantine).
Tetragonal crystal system This page was last edited on 31 December 2022, at 16:52 (UTC). Text is available under the Creative Commons Attribution-ShareAlike 4.0 ...
Crystal systems that have space groups assigned to a common lattice system are combined into a crystal family. The seven crystal systems are triclinic, monoclinic, orthorhombic, tetragonal, trigonal, hexagonal, and cubic. Informally, two crystals are in the same crystal system if they have similar symmetries (though there are many exceptions).
Two growth habits of anatase crystals may be distinguished. The more common occurs as simple acute octahedra with an indigo-blue to black color and steely luster. Crystals of this kind are abundant at Le Bourg-d'Oisans in Dauphiné, France, where they are associated with rock-crystal, feldspar, and axinite in crevices in granite and mica schist.
Optical properties of common minerals Name Crystal system Indicatrix Optical sign Birefringence Color in plain polars Anorthite: Triclinic: Biaxial (-) 0.013